Rewrite TODO.md sentence by sentence (closes #135)

TODO.md is the project's own task list, judged by the same rules as
README.md: short sentences, lists as bullets, nothing a newcomer reads
twice. Every completed step is kept with its date and its issue or
branch, and every fact the old entries recorded is kept too, in short
sentences. The 2026-07-22 policy-compliance checklist is folded into
the step that did the work, and the accepted divergence from the
layout policy gets a section of its own. Workflow, Status and Next
Step keep their rules unchanged.

Model: fable-5-1

TODO.md

@@ -20,7 +20,7 @@
 
 # Next Step
 
-- Take the next issue from the `1.0.0` milestone:
+- Take the next issue from the `1.0.0` milestone,
   https://git.eeqj.de/sneak/sfdupes/milestone/17. The issues are not restated
   here, because a copy drifts as soon as the tracker moves.
 
@@ -29,33 +29,32 @@
 Newest first. An entry ends with its date and its issue or branch, where those
 are known.
 
-- `TODO.md` rewritten from scratch by the same rules as `README.md`: short
-  sentences, lists as bullets, nothing a newcomer reads twice. Every completed
-  step is kept, with its date and its issue or branch. The policy-compliance
-  checklist of 2026-07-22 is folded into its step (2026-10-26,
-  https://git.eeqj.de/sneak/sfdupes/issues/135)
+- `TODO.md` rewritten from scratch by the same rules as `README.md`, sentence by
+  sentence. Every completed step is kept, with its date and its issue or branch.
+  The policy-compliance checklist of 2026-07-22 is folded into its step
+  (2026-10-26, https://git.eeqj.de/sneak/sfdupes/issues/135)
 
 - `README.md` rewritten from scratch, sentence by sentence, as a newcomer reads
   it. It leads with what the program is and how to use it. A reference section
-  covers the settings, the database, the output formats and the exit codes;
-  development and testing come last. Every statement was checked against the
-  code on `next`. Three comments in `main_test.go` cite "Settings", where their
-  rules now live (2026-10-26, https://git.eeqj.de/sneak/sfdupes/issues/135)
+  covers every setting and every subcommand. Development and testing come last.
+  Every statement was checked against the code on `next`. Three comments in
+  `main_test.go` cite "Settings", where their rules now live (2026-10-26,
+  https://git.eeqj.de/sneak/sfdupes/issues/135)
 
 - A file or directory removed while the scan runs is not an error, in the walk
   or in the hash phase. The scan prints no line for it and does not count it as
   skipped. When the first of several hard links to a file is gone, the hash
   phase reads the next one instead. On a terminal every progress display starts
   with the spinner, the hash phase's included. A phase with an exact total ends
-  its line with its percent and a 10-column bar at the terminal's right edge,
-  which no longer moves as the line's length changes. A line too wide for the
+  its line with its percent and a 10-column bar at the terminal's right edge.
+  The bar no longer moves as the line's length changes. A line too wide for the
   terminal now loses its rate before its bar. The time remaining is labelled
   `remain`, not `eta` (2026-10-26, https://git.eeqj.de/sneak/sfdupes/issues/133)
 
 - The `head`, `tail` and `content` columns are BLOBs, each holding the raw 32
-  bytes of a SHA-256, half the size of the hex text they held. The hashes stay
-  raw from the hash phase through the database to `report` and `trees`. Reading
-  a record whose hash is not 32 bytes is an error (2026-10-26,
+  bytes of a SHA-256. That is half the size of the hex text they held. The
+  hashes stay raw from the hash phase through the database to `report` and
+  `trees`. Reading a record whose hash is not 32 bytes is an error (2026-10-26,
   https://git.eeqj.de/sneak/sfdupes/issues/134)
 
 - Every file the walk records gets three hashes in the hash phase. `head` and
@@ -63,9 +62,9 @@ are known.
   of the whole file under 100 MiB, and of 1 MiB at each gigabyte from 100 MiB
   up. Gone are:
     - the 10 MiB and 50 MiB thresholds;
-    - the size census: the sizes of every walked file and of every record
-      outside the operands, by which a file was hashed only when another file
-      shared its size;
+    - the size census, which counted the sizes of every walked file and of every
+      record outside the operands. A file was hashed only when the census showed
+      another file of its size;
     - the records without hashes;
     - the content phase.
 
@@ -74,73 +73,109 @@ are known.
     with a content hash, since every record has all three (2026-10-25,
     https://git.eeqj.de/sneak/sfdupes/issues/132)
 
-- `REPO_POLICIES.md` and the four scripts that pass `CACHEBUST` re-vendored from
-  `sneak/prompts` `next` at `0653579`. Two steps now come before
-  `ARG CACHEBUST`: the module download in the `lint`, `test` and `builder`
-  stages of the `Dockerfile`, and the package install in `builder`. Docker keeps
-  them until the base image, the install line, `go.mod` or `go.sum` changes.
-  Every step that lints, tests or compiles still comes after it.
-  `golangci-lint run` also keeps the linter's own cache. README says the same
-  (2026-10-18, https://git.eeqj.de/sneak/sfdupes/issues/109)
+- `REPO_POLICIES.md` and the four scripts that pass `CACHEBUST` copied again
+  from `sneak/prompts` `next` at `0653579`. Two steps now come before
+  `ARG CACHEBUST`:
+    - the module download in the `lint`, `test` and `builder` stages of the
+      `Dockerfile`;
+    - the package install in `builder`.
 
-- Release rule set: until 1.0, each tip of `main` that passes the build gets the
-  next `v0.0.N` tag, so `go install sneak.berlin/go/sfdupes@latest` installs it.
-  `go.mod` retracts `v0.0.1`, the early build without a database. When the
+    Docker keeps them until one of these changes:
+    - the base image;
+    - the install line;
+    - `go.mod` or `go.sum`.
+
+    Every step that checks or compiles the code still comes after
+    `ARG CACHEBUST`. `golangci-lint run` also keeps the linter's own cache.
+    README says the same (2026-10-18,
+    https://git.eeqj.de/sneak/sfdupes/issues/109)
+
+- Release rule set. Until 1.0, each tip of `main` that passes the build gets the
+  next `v0.0.N` tag. `go install sneak.berlin/go/sfdupes@latest` then installs
+  it. `go.mod` retracts `v0.0.1`, the early build without a database. When the
   linker set no version, `sfdupes --version` prints the version Go recorded in
-  the binary: the tag, or the pseudo-version of a `go install` build. It prints
-  `dev` only when neither is known. README "Install" documented the rule, what
-  `@main` and `v0.0.1` give, and how to check an installed binary (2026-10-17,
-  https://git.eeqj.de/sneak/sfdupes/issues/116)
+  the binary. That is the tag, or the pseudo-version of a `go install` build. It
+  prints `dev` only when neither is known. README "Install" documented:
+    - the rule;
+    - what `@main` and `v0.0.1` give;
+    - how to check an installed binary.
+
+    (2026-10-17, https://git.eeqj.de/sneak/sfdupes/issues/116)
 
 - `scan` creates the database's directory where the database path leads. The
-  directory is the path with its last element cut off as text, never cleaned. A
-  `..` after a symlinked directory therefore goes through the symlink, as it
-  does when the file is opened. With
+  directory is the path with its last element cut off as text, so a `..` in it
+  stays. A `..` after a symlinked directory therefore goes through the symlink,
+  as it does when the file is opened. With
   `SFDUPES_DATABASE=/srv/link/../new/db.sqlite` and `/srv/link` a symlink to
   `/data/x`, it now creates `/data/new` and the database in it. It used to
   create `/srv/new` and then fail (2026-10-17,
   https://git.eeqj.de/sneak/sfdupes/issues/119)
 
 - `scan` never records its own database. Once the database and its `.lock` file
-  are open, it notes the device and inode of the database file, its `-wal` and
-  `-shm` files and the `.lock` file. The walk passes over a file with one of
-  them wherever it reaches it, through a symlinked directory included, printing
-  no line and counting nothing. A record an earlier scan left for one of them is
-  deleted (2026-10-17, https://git.eeqj.de/sneak/sfdupes/issues/115)
+  are open, it notes the device and inode of each of these:
+    - the database file;
+    - its `-wal` and `-shm` files;
+    - the `.lock` file.
 
-- `scan` never records or reads anything on a filesystem that is not persistent:
-  `tmpfs`, `proc`, `sysfs` and the other kernel or memory-backed types. It
-  matches them by device ID, however the walk or the content phase reaches a
-  path. As the scan starts, it lists the mounted filesystems of those types,
-  from `/proc/self/mountinfo` on Linux and from the mount list on macOS. No flag
-  turns that off. Below an operand, the walk does not enter the default excludes
-  either, so `sfdupes scan /` skips the kernel's view of the running system and
-  the temporary directories. On Linux those are `/proc`, `/sys`, `/dev`, `/run`,
-  `/tmp` and `/var/tmp`. On macOS they are `/dev`, `/private/tmp`,
-  `/private/var/tmp`, `/private/var/vm`, `/System/Volumes/VM` and
-  `/System/Volumes/Data`. A Windows list exists in the code but is not used. An
-  operand at or inside a default exclude is still walked. The scan prints a line
-  for each path it leaves out, without counting it as skipped, and the records
-  there count as outside the scanned operands, as for `-x`.
-  `--no-default-excludes` turns off the default excludes only, and `scan --help`
-  lists them (2026-10-17, https://git.eeqj.de/sneak/sfdupes/issues/124)
+    The walk passes over any file with the device and inode of one of them,
+    however it reaches the file. It prints no line for such a file and counts
+    nothing. A record an earlier scan left for one of them is deleted
+    (2026-10-17, https://git.eeqj.de/sneak/sfdupes/issues/115)
+
+- `scan` never records or reads anything on a filesystem that is not persistent,
+  such as `tmpfs` or `proc`. Such a filesystem is one the kernel makes up or
+  keeps in memory. `scan` matches them by device ID, however the walk or the
+  content phase reaches a path. As the scan starts, it lists the mounted
+  filesystems of those types, from `/proc/self/mountinfo` on Linux and from the
+  mount list on macOS. No flag turns that off. Below an operand, the walk does
+  not enter the default excludes either. So `sfdupes scan /` skips the kernel's
+  view of the running system and the temporary directories. On Linux those are:
+
+    ```
+    /proc, /sys, /dev, /run, /tmp, /var/tmp
+    ```
+
+    On macOS they are:
+
+    ```
+    /dev, /private/tmp, /private/var/tmp, /private/var/vm
+    /System/Volumes/VM, /System/Volumes/Data
+    ```
+
+    A Windows list exists in the code but is not used. An operand at or inside a
+    default exclude is still walked. The scan prints a line for each path it
+    leaves out, without counting it as skipped. The records there count as
+    outside the scanned operands, as for `-x`. `--no-default-excludes` turns off
+    the default excludes only, and `scan --help` lists them (2026-10-17,
+    https://git.eeqj.de/sneak/sfdupes/issues/124)
 
 - The rate a progress display shows covers the items completed over the last 5
-  seconds, or since the line before when stderr is not a terminal. It falls to 0
-  while nothing completes, and a burst after a wait no longer reads as a steady
-  rate of over 1,000 files a second. The time remaining still comes from the
-  phase's average. Once no item has completed for 10 seconds, the word `stalled`
-  and where the phase waits take the rate's place, as `stalled disk/db`. The
-  places are `disk`, `db`, `out` for stdout and `cpu`, or two of them for a
-  phase that may wait on either. Each phase's word is set in the code that
-  defines the phase. A line too wide for the terminal loses its bar first, then
-  its rate or those words, so the phase, progress, elapsed time and ETA stay
-  whole. On an 80-column terminal, at counts like those of README's example, the
-  content phase's displays for its checks and its reads lost those words. That
-  happened for most elapsed times and ETAs in minutes. Every other phase kept
-  them whenever the elapsed time and the ETA were both in minutes. The content
-  phase's last partial batch is written under a display of its own (2026-10-16,
-  https://git.eeqj.de/sneak/sfdupes/issues/125)
+  seconds. When stderr is not a terminal, it covers the items since the line
+  before. It falls to 0 while nothing completes. A burst after a wait no longer
+  reads as a steady rate of over 1,000 files a second. The time remaining still
+  comes from the phase's average. Once no item has completed for 10 seconds, the
+  word `stalled` and where the phase waits take the rate's place, as
+  `stalled disk/db`. The places are:
+    - `disk`;
+    - `db`;
+    - `out`, for stdout;
+    - `cpu`.
+
+    A phase that may wait in two places names both. Each phase's word is set in
+    the code that defines the phase. A line too wide for the terminal loses its
+    bar first, then its rate or those words. Four parts stay whole:
+    - the phase;
+    - the progress;
+    - the elapsed time;
+    - the ETA, the time remaining.
+
+    On an 80-column terminal, at counts like those of README's example, the
+    content phase's displays for its checks and its reads lost those words. That
+    happened for most elapsed times and ETAs in minutes. Every other phase kept
+    them whenever the elapsed time and the ETA were both in minutes. The content
+    phase writes its last partial batch, the records not yet written, under a
+    display of its own (2026-10-16,
+    https://git.eeqj.de/sneak/sfdupes/issues/125)
 
 - New subcommand `info` prints the database's details on stdout, one per line as
   a name, a tab and the value:
@@ -148,13 +183,15 @@ are known.
     - the sizes of the database file and of its `-wal` file, when there is one;
     - when the database file was last changed;
     - the schema version;
-    - the number of records, how many have `head` and `tail` hashes, and how
-      many have a content hash;
+    - the number of records;
+    - how many records have `head` and `tail` hashes;
+    - how many records have a content hash;
     - the sizes of all records added up.
 
     It opens the database as `report` does and shows two phases on stderr,
     `[1/2] open` and `[2/2] count`. The schema version and the counts come from
-    one read-only transaction, the counts from one query (2026-10-16,
+    one read-only transaction, a read of the database at one moment. The counts
+    come from one query (2026-10-16,
     https://git.eeqj.de/sneak/sfdupes/issues/117)
 
 - `report` shows its work on stderr in two phases, `[1/2] open` and
@@ -163,68 +200,75 @@ are known.
   opening the database, also while it waits on a busy one. `read` counts the
   records, then reads them against that count in signature order. SQLite takes
   that order from the `files_signature` index without sorting, so the first
-  record comes at once. `report` forms the duplicate groups itself, holding only
-  those of the size it is reading, and writes them ordered by first path before
-  it reads the next size. stdout and the summary line are unchanged, and SQLite
-  no longer needs a temporary file to sort in (2026-10-16,
+  record comes at once. `report` forms the duplicate groups itself and holds
+  only those of the size it is reading. It writes them ordered by first path
+  before it reads the next size. stdout and the summary line are unchanged, and
+  SQLite no longer needs a temporary file to sort in (2026-10-16,
   https://git.eeqj.de/sneak/sfdupes/issues/114)
 
-- `trees` shows its work on stderr in four phases, `[1/4] open`, `[2/4] read`,
-  `[3/4] group` and `[4/4] write`, each with the progress display `scan` uses.
-  The display runs from the moment `trees` starts until the summary line. `open`
-  says it is opening the database, also while it waits on a busy one. `read`
-  counts the records, then reads them against that count. `group` counts the
-  directories it groups, and `write` the groups it writes. A display's rate
-  names what its phase counts: files, records, directories or groups. stdout and
-  the summary line are unchanged. When stdout and stderr are the same file, as
-  one terminal is, no line of stdout shares a line with the display. When they
-  are not, the display keeps being drawn while stdout waits on a slow reader
-  (2026-10-16, https://git.eeqj.de/sneak/sfdupes/issues/113)
+- `trees` shows its work on stderr in four phases, from `[1/4] open` to
+  `[4/4] write`, each with the progress display `scan` uses. The display runs
+  from the moment `trees` starts until the summary line. `open` says it is
+  opening the database, also while it waits on a busy one. `read` counts the
+  records, then reads them against that count. `group` counts the directories it
+  groups, and `write` the groups it writes. A display's rate names what its
+  phase counts, such as records or groups. stdout and the summary line are
+  unchanged. When stdout and stderr are the same file, as one terminal is, no
+  line of stdout shares a line with the display. When they are not, the display
+  keeps being drawn while stdout waits on a slow reader (2026-10-16,
+  https://git.eeqj.de/sneak/sfdupes/issues/113)
 
 - Each `scan` phase's progress display names the phase and its place among the
-  five, as `[2/5] walk`. It runs from the moment the phase starts and shows its
-  progress, elapsed time and ETA. `load` counts the records first. The walk's
-  total is estimated from the records under the operands. The content phase
-  counts the records it checks from SQLite's grouping alone, then says it is
-  searching the database until the first one is returned. On a terminal a phase
-  with an exact total draws its line followed by the library's bar. Any other
-  phase draws a spinner followed by the line. Every display is drawn again
-  several times a second. No line reaches the terminal's last column, however
-  narrow, also after the terminal is made narrower during a phase. A line too
-  wide leaves out its rate, then its bar, keeping the phase, progress, elapsed
-  time and ETA whole. It is cut short only when those alone do not fit, as below
-  about 70 columns late in a large scan. When stderr is not a terminal, the line
-  is printed every 5 seconds whether or not an item completed (2026-10-16,
-  https://git.eeqj.de/sneak/sfdupes/issues/112)
+  five, as `[2/5] walk`. It runs from the moment the phase starts and shows:
+    - the progress;
+    - the elapsed time;
+    - the ETA, the time remaining.
+
+    `load` counts the records first. The walk's total is estimated from the
+    records under the operands. The content phase takes its total from SQLite's
+    grouping alone. Until the first record is returned, it says it is searching
+    the database. On a terminal a phase with an exact total draws its line
+    followed by the bar of the progress-bar library. Any other phase draws a
+    spinner followed by the line. Every display is drawn again several times a
+    second. No line reaches the terminal's last column, however narrow the
+    terminal is, even after it is made narrower during a phase. A line too wide
+    leaves out its rate, then its bar. The rest stays whole. The line is cut
+    short only when the rest alone does not fit, as below about 70 columns late
+    in a large scan. When stderr is not a terminal, the line is printed every 5
+    seconds whether or not an item completed (2026-10-16,
+    https://git.eeqj.de/sneak/sfdupes/issues/112)
 
 - `scan`, `report` and `trees` first print a line on stderr naming the database
-  they use, as an absolute path, and whether that path is the default or comes
-  from `SFDUPES_DATABASE`. `scan` says when the database is new. README
+  they use, as an absolute path. The line says whether that path is the default
+  or comes from `SFDUPES_DATABASE`. `scan` says when the database is new. README
   "Database" says when `scan` writes each file (2026-10-16,
   https://git.eeqj.de/sneak/sfdupes/issues/111)
 
-- The canonical files and model scripts re-vendored from `sneak/prompts` `next`
+- The canonical files and model scripts copied again from `sneak/prompts` `next`
   at `e3f79c4`:
     - `golangci-lint` v2.14.0;
     - lint and test are phases of the `Dockerfile` that write no image, and
-      `make test` runs the suite under the race detector. `Dockerfile.lint`,
-      `script/verify-lint-image-pin` and `make test-race` are gone;
-    - every `docker build` in `script/` passes a new `CACHEBUST` value, which
-      every stage of the `Dockerfile` declares first, so every `RUN` step runs
-      on every build. The steps that compile keep Go's build cache, and the
-      tests run with `-count=1`;
+      `make test` runs the suite under the race detector. Gone are
+      `Dockerfile.lint`, `script/verify-lint-image-pin` and `make test-race`;
+    - every `docker build` in `script/` passes a new `CACHEBUST` value. Every
+      stage of the `Dockerfile` declares it first, so every `RUN` step runs on
+      every build. The steps that compile keep Go's build cache, and the tests
+      run with `-count=1`;
     - `prettier` runs on the host, from the `node` and `yarn` that
-      `script/bootstrap` installs, so the `prettier` and `markdown` stages are
-      gone and the build stage installs `git` and `make` itself;
+      `script/bootstrap` installs. The `prettier` and `markdown` stages are
+      gone, and the build stage installs `git` and `make` itself;
     - a new push cancels the workflow's older run on the same branch, and a run
       stops after 20 minutes;
-    - `.claude/settings.json` is deleted.
+    - a stray editor-settings file is deleted.
 
     Since https://git.eeqj.de/sneak/sfdupes/issues/109 two steps come before
-    `ARG CACHEBUST`: the module download in `lint`, `test` and the build stage,
-    and the install of `git` and `make` in the build stage. Docker keeps them
-    between builds, and every step that lints, tests or compiles still runs on
-    every build (2026-10-15, https://git.eeqj.de/sneak/sfdupes/issues/95)
+    `ARG CACHEBUST`:
+    - the module download in `lint`, `test` and the build stage;
+    - the install of `git` and `make` in the build stage.
+
+    Docker keeps them between builds. Every step that checks or compiles the
+    code still runs on every build (2026-10-15,
+    https://git.eeqj.de/sneak/sfdupes/issues/95)
 
 - With `-x`, an operand under another operand is no longer dropped when the
   outer operand's walk cannot reach it. That is the case when a directory
@@ -235,8 +279,8 @@ are known.
   https://git.eeqj.de/sneak/sfdupes/issues/106)
 
 - With `-x`, `scan` keeps the records below a directory on another filesystem
-  under its operand, and counts their sizes in the size census, instead of
-  deleting them (2026-10-14, https://git.eeqj.de/sneak/sfdupes/issues/99)
+  under its operand, instead of deleting them. It counts their sizes in the size
+  census (2026-10-14, https://git.eeqj.de/sneak/sfdupes/issues/99)
 
 - The hash and content phases open each file without blocking and check that it
   is still a regular file. A file replaced by a FIFO or device node after it was
@@ -266,12 +310,12 @@ are known.
 - `make test-race` ran the test suite under the race detector in a cgo-enabled
   container, outside `make check`. Since
   https://git.eeqj.de/sneak/sfdupes/issues/95 `make test` itself runs the suite
-  under the race detector, in the `Dockerfile`'s Debian-based `test` phase, and
+  under the race detector, in the `Dockerfile`'s Debian-based `test` phase.
   `make test-race` is gone (2026-10-04,
   https://git.eeqj.de/sneak/sfdupes/issues/18)
 
 - A bare `docker build .` failed, naming `script/cibuild` and `script/docker`,
-  rather than serve the gates from cache. Since
+  rather than serve the gates, the lint and test steps, from cache. Since
   https://git.eeqj.de/sneak/sfdupes/issues/95 a bare build succeeds, as
   `REPO_POLICIES.md` requires, and may serve the gates from cache. The builds in
   `script/` pass a new `CACHEBUST` value, so theirs always run (2026-10-04,
@@ -284,9 +328,14 @@ are known.
 - `script/lint` writes no image, so a run no longer leaves an untagged one
   behind (2026-10-04, https://git.eeqj.de/sneak/sfdupes/issues/48)
 
-- Tests cover a missing database, `scan` keeping stdout empty, its skip warning,
-  the `report` and `trees` summary lines, and every subcommand going through
-  `runE` (2026-10-04, https://git.eeqj.de/sneak/sfdupes/issues/16)
+- Tests cover:
+    - a missing database;
+    - `scan` keeping stdout empty;
+    - its skip warning;
+    - the `report` and `trees` summary lines;
+    - every subcommand going through `runE`.
+
+    (2026-10-04, https://git.eeqj.de/sneak/sfdupes/issues/16)
 
 - `.golangci.yml` replaced with the current canonical copy, which uses
   `gomodguard_v2`, so lint no longer prints a deprecation warning (2026-10-04,
@@ -324,7 +373,7 @@ are known.
 - The `Dockerfile` build stage kept the Go module cache out of `builder`'s home
   and copied the sources with `--chown`, so no `chown -R` walked them. Since
   https://git.eeqj.de/sneak/sfdupes/issues/95 there is no `builder` user and
-  nothing changes owner: the build stage only compiles, as root, and the tests
+  nothing changes owner. The build stage only compiles, as root, and the tests
   run as `nobody` in the `test` phase (2026-10-04,
   https://git.eeqj.de/sneak/sfdupes/issues/43)
 
@@ -339,13 +388,19 @@ are known.
   The schema gains the `files_signature` index (2026-10-04,
   https://git.eeqj.de/sneak/sfdupes/issues/14)
 
-- Progress prints at once on a non-terminal, uses a real terminal test, and
-  prints warnings through a spinner instead of racing its redraw (2026-10-03,
+- Progress prints at once on a non-terminal and uses a real terminal test.
+  Warnings print through a spinner instead of racing its redraw (2026-10-03,
   https://git.eeqj.de/sneak/sfdupes/issues/13)
 
-- Symlink, socket, FIFO, device and `.zfs` operands are warned about and
-  skipped, and the records beneath them are kept (2026-10-03,
-  https://git.eeqj.de/sneak/sfdupes/issues/9)
+- These operands are warned about and skipped, and the records beneath them are
+  kept:
+    - symlinks;
+    - sockets;
+    - FIFOs;
+    - device nodes;
+    - `.zfs` directories.
+
+    (2026-10-03, https://git.eeqj.de/sneak/sfdupes/issues/9)
 
 - `scan` holds a lock on a lock file beside the database for its whole run, so a
   second `scan` fails at once with exit 1 (2026-10-03,
@@ -359,9 +414,14 @@ are known.
   WAL mode, so reading needs only read access (2026-10-03,
   https://git.eeqj.de/sneak/sfdupes/issues/8)
 
-- Tabs, newlines, carriage returns and backslashes are escaped in report, trees
-  and warning paths. The root directory's path is `/` (2026-10-03,
-  https://git.eeqj.de/sneak/sfdupes/issues/7)
+- Four characters are escaped in `report`, `trees` and warning paths:
+    - tab;
+    - newline;
+    - carriage return;
+    - backslash.
+
+    The root directory's path is `/` (2026-10-03,
+    https://git.eeqj.de/sneak/sfdupes/issues/7)
 
 - A plain `docker build .` stamps the `git` tag or short commit instead of
   `dev`. `.dockerignore` sends `.git` without `.git/config`. The build stage
@@ -375,14 +435,14 @@ are known.
   size, and README "Duplicate detection" documented every size threshold. A file
   under 10 MiB was hashed in full, and its `head`, `tail` and `content` all held
   that hash. A larger file got only its 64 KiB `head` and `tail` in the hash
-  phase. The content phase, after the update phase, read it for `content` only
-  when its size, `head` and `tail` matched another record's, from this scan or
-  an earlier one. `content` was the whole file below 50 MiB, and gigabyte-spaced
-  1 MiB samples at or above. A file gone or changed since its record was written
-  was never read. `report` and `trees` left out any record without a `content`
-  hash. The `content` column is part of the version 1 schema. Superseded by
-  https://git.eeqj.de/sneak/sfdupes/issues/132 (2026-09-22, branch `next`,
-  https://git.eeqj.de/sneak/sfdupes/issues/61)
+  phase. The content phase ran after the update phase. It read a file for
+  `content` only when its size, `head` and `tail` matched another record's, from
+  this scan or an earlier one. `content` was the whole file below 50 MiB, and
+  gigabyte-spaced 1 MiB samples at or above. A file gone or changed since its
+  record was written was never read. `report` and `trees` left out any record
+  without a `content` hash. The `content` column is part of the version 1
+  schema. Superseded by https://git.eeqj.de/sneak/sfdupes/issues/132
+  (2026-09-22, branch `next`, https://git.eeqj.de/sneak/sfdupes/issues/61)
 
 - The dead `files.dat` references removed from `Makefile`, `.gitignore` and
   `.dockerignore` (2026-09-21, branch `next`,
@@ -393,8 +453,8 @@ are known.
   `# image:vX.Y.Z, YYYY-MM-DD` comment over a bare `FROM image@sha256:...`,
   without the false `(Debian-based)` note or the tag. Since
   https://git.eeqj.de/sneak/sfdupes/issues/95 the `Dockerfile`'s `lint` phase
-  holds the only `golangci-lint` pin, in that form. `Dockerfile.lint` and
-  `script/verify-lint-image-pin`, which compared the two pins, are gone
+  holds the only `golangci-lint` pin, in that form. `Dockerfile.lint` is gone,
+  and so is `script/verify-lint-image-pin`, which compared the two pins
   (2026-08-10, branch `next`, https://git.eeqj.de/sneak/sfdupes/issues/25)
 
 - All linting ran in Docker, via `Dockerfile.lint` and `script/lint`. Per the
@@ -403,8 +463,8 @@ are known.
   `script/bootstrap` stopped installing or pinning the linter, and
   `script/verify-linter-pin` was retired. Since
   https://git.eeqj.de/sneak/sfdupes/issues/95 both commands run in the
-  `Dockerfile`'s `lint` phase, which `script/lint` builds alone and the build
-  stage depends on through `COPY --from=lint /src/go.sum /dev/null`.
+  `Dockerfile`'s `lint` phase. `script/lint` builds that phase alone, and the
+  build stage depends on it through `COPY --from=lint /src/go.sum /dev/null`.
   `Dockerfile.lint` and `script/verify-lint-image-pin` are gone. Nothing inside
   an image build may run `docker`, so the phase calls `golangci-lint` directly
   (2026-08-10, branch `next`, https://git.eeqj.de/sneak/sfdupes/issues/46)
@@ -413,38 +473,43 @@ are known.
   `script/bootstrap` instead of `apk add --no-cache make` inline.
   `script/verify-linter-pin` failed the build unless the linter copied from the
   lint stage was the version `script/bootstrap` pinned. Builds then took up to
-  5m14s cold, mostly in a `chown -R` of the module cache, filed as
-  https://git.eeqj.de/sneak/sfdupes/issues/43. Since
+  5m14s from an empty cache, mostly in a `chown -R` of the module cache, filed
+  as https://git.eeqj.de/sneak/sfdupes/issues/43. Since
   https://git.eeqj.de/sneak/sfdupes/issues/95 the build stage installs `git` and
-  `make` with `apk add --no-cache` and only compiles; the `lint` and `test`
+  `make` with `apk add --no-cache` and only compiles. The `lint` and `test`
   phases are the gates (2026-08-09, branch `dockerfile-bootstrap`,
   https://git.eeqj.de/sneak/sfdupes/issues/42)
 
-- The Docker layer cache is busted for the gate steps, so `script/cibuild` and
-  `script/docker` cannot report a green they did not earn. The `Dockerfile`
-  copies the tree before its gates, so on an unchanged tree Docker served them
-  from cache and the build exited 0 having run nothing. The fix was a
+- The Docker layer cache is defeated for the gate steps, so `script/cibuild` and
+  `script/docker` cannot report a pass they did not earn. The `Dockerfile`
+  copies the tree before its gates. On an unchanged tree Docker served them from
+  cache, and the build exited 0 without running them. The fix was a
   `CHECK_EPOCH` build argument. Since
   https://git.eeqj.de/sneak/sfdupes/issues/95 every `docker build` in `script/`
-  passes a new `CACHEBUST` value instead, which every stage of the `Dockerfile`
-  declares before every step that lints, tests or compiles. Run as root, the
-  tests fail `TestScanHardlinkRunFailsTogether`, because root reads through the
-  `chmod(0)` the test relies on, so the `test` phase runs them as `nobody`
+  passes a new `CACHEBUST` value instead. Every stage of the `Dockerfile`
+  declares it before every step that checks or compiles the code. Run as root,
+  the tests fail `TestScanHardlinkRunFailsTogether`, because root reads through
+  the `chmod(0)` the test relies on. So the `test` phase runs them as `nobody`
   (2026-08-09, branch `cibuild-cache-bust`,
   https://git.eeqj.de/sneak/sfdupes/issues/32)
 
 - `script/bootstrap` checked the installed `golangci-lint` version instead of
   only its presence. The version lived only in `GOLANGCI_LINT_VERSION`, with the
-  `go install` module ref derived from it. Any installed version that was not
-  the pin was reinstalled: older, newer, absent or unparseable. `go install`
-  writes into `GOBIN` (or `GOPATH/bin`) while `make lint` ran the first
-  `golangci-lint` on `PATH`, so bootstrap re-read the effective version after
-  installing. On a mismatch it printed both paths and both versions and exited
-  non-zero; it did not reorder `PATH` or delete anyone's binary. The `--version`
-  call kept its stderr and was bounded by `timeout(1)` where that exists. `git`,
-  `make` and `go` kept presence-only checks. The version check was verified by
-  bootstrapping this host from v2.10.1 to v2.12.2, and again to a no-op. Stub
-  runs of the script under `dash` covered:
+  `go install` module reference derived from it. Any installed version that was
+  not the pin was reinstalled, whether:
+    - older;
+    - newer;
+    - absent;
+    - unparseable.
+
+    `go install` writes into `GOBIN`, or `GOPATH/bin`, while `make lint` ran the
+    first `golangci-lint` on `PATH`. So bootstrap re-read the effective version
+    after installing. On a mismatch it printed both paths and both versions and
+    exited non-zero. It did not reorder `PATH` or delete anyone's binary. The
+    `--version` call kept its stderr and was bounded by `timeout(1)` where that
+    exists. `git`, `make` and `go` kept presence-only checks. The version check
+    was verified by bootstrapping this host from v2.10.1 to v2.12.2, and again
+    to a no-op. Stub runs of the script under `dash` covered:
     - a thirteen-input version-parse matrix;
     - a shadowed install, which must exit non-zero;
     - an install destination not on `PATH`;
@@ -453,7 +518,7 @@ are known.
 
     `make check` and `make lint` were clean at v2.12.2, so v2.10.1 had not been
     hiding findings on `main`. Superseded by
-    https://git.eeqj.de/sneak/sfdupes/issues/46: the linter is no longer
+    https://git.eeqj.de/sneak/sfdupes/issues/46, since the linter is no longer
     installed on a host (2026-08-09, branch `bootstrap-version-check`,
     https://git.eeqj.de/sneak/sfdupes/issues/24)
 
@@ -461,45 +526,66 @@ are known.
   context-aware `hashPool`. Every blocking send in the feeder and the workers
   selects on `ctx.Done()`, and `jobs` is closed on every path out. `hashPhase`
   defers `pool.stop()`, which cancels and then drains `results` until the last
-  goroutine has exited; draining is what frees a worker parked on a send. `ctx`
-  is threaded from `cmd.Context()` through `runScan`, `syncScan`, both worker
-  pools and the whole database layer, as the first parameter everywhere. The
-  walk pool gets the same treatment, plus a `ctx.Err()` guard after the walk. A
-  cancelled walk yields a partial size census, and every file it never reached
-  looks vanished to the update phase. That phase's own `BeginTx` also fails on
-  the cancelled context before deleting anything. The guard is still the barrier
-  once an interrupted scan may commit what it has. Tests drive `run(scan)`
-  against a database whose insert trigger aborts, and assert that the scan fails
-  instead of hanging and that the goroutine count returns to its pre-scan
-  baseline. Other tests cancel a scan part-way through the walk,
-  deterministically, by counting the scan's own checks of `ctx.Done()`. They
-  assert that it stops at the guard, holding a partial size census and a
-  still-populated record index, with every record intact. Direct tests of
-  `sendEvent`, the walk workers, `dispatchDirs`, `feedHashJobs`, `hashWorker`
-  and `hashPhase` cover the remaining cancellation branches of both pools
-  (2026-08-09, branch `hash-pool-cleanup`,
-  https://git.eeqj.de/sneak/sfdupes/issues/6)
+  goroutine has exited. Draining is what frees a worker parked on a send. `ctx`
+  is passed from `cmd.Context()` as the first parameter, through:
+    - `runScan`;
+    - `syncScan`;
+    - both worker pools;
+    - the whole database layer.
+
+    The walk pool gets the same treatment, plus a `ctx.Err()` guard after the
+    walk. A cancelled walk yields a partial size census, and every file it never
+    reached looks vanished to the update phase. That phase's own `BeginTx` also
+    fails on the cancelled context before deleting anything. The guard is still
+    the barrier once an interrupted scan may commit what it has. Tests drive
+    `run(scan)` against a database whose insert trigger aborts. They assert that
+    the scan fails instead of hanging, and that the goroutine count returns to
+    its pre-scan baseline. Other tests cancel a scan part-way through the walk,
+    deterministically, by counting the scan's own checks of `ctx.Done()`. They
+    assert that it stops at the guard with every record intact. It then holds a
+    partial size census and a still-populated record index. Direct tests cover
+    the remaining cancellation branches of both pools. They test:
+    - `sendEvent`;
+    - the walk workers;
+    - `dispatchDirs`;
+    - `feedHashJobs`;
+    - `hashWorker`;
+    - `hashPhase`.
+
+    (2026-08-09, branch `hash-pool-cleanup`,
+    https://git.eeqj.de/sneak/sfdupes/issues/6)
 
 - The database is closed on every fatal exit path. `fatalf` and its `os.Exit(1)`
-  are gone, so the deferred `db.Close()`, and with it the SQLite WAL checkpoint,
-  runs when a subcommand fails. `runScan`, `runReport`, `runTrees`,
-  `loadRecords` and `resolveRoots` return errors instead. The single exit point
-  is `run` in `main.go`. It maps a `fatalError`, anything a subcommand returned,
-  to exit 1, and cobra's own argument and flag errors to exit 2. So a runtime
-  failure is never reported as a usage error, nor printed with the usage text.
-  `main_test.go` drives the CLI in-process and asserts the exit codes from
-  README "Error handling" and the stdout/stderr split. It also checks that a
-  fatal error after the database is open leaves no `-wal` or `-shm` file behind,
-  for `scan`, `report` or `trees` (2026-08-09, branch `db-close-on-fatal`,
-  https://git.eeqj.de/sneak/sfdupes/issues/4)
+  are gone. So the deferred `db.Close()` runs when a subcommand fails, and with
+  it the SQLite WAL checkpoint. These return errors instead:
+    - `runScan`;
+    - `runReport`;
+    - `runTrees`;
+    - `loadRecords`;
+    - `resolveRoots`.
+
+    The single exit point is `run` in `main.go`. It maps a `fatalError`,
+    anything a subcommand returned, to exit 1, and cobra's own argument and flag
+    errors to exit 2. So a runtime failure is never reported as a usage error,
+    nor printed with the usage text. `main_test.go` drives the CLI in-process
+    and asserts the exit codes from README "Error handling" and the
+    stdout/stderr split. It also checks that a fatal error after the database is
+    open leaves no `-wal` or `-shm` file behind, for `scan`, `report` or `trees`
+    (2026-08-09, branch `db-close-on-fatal`,
+    https://git.eeqj.de/sneak/sfdupes/issues/4)
 
 - `golangci-lint` updated to v2.12.2 with the canonical config, merged as
   `38a01bd`. The pinned linter in the `Dockerfile` lint stage and
   `script/bootstrap` went from v2.12.1 to v2.12.2, and `.golangci.yml` was
-  replaced with the canonical file. The linter settings (`lll`, `funlen`,
-  `cyclop`, `dupl` thresholds) now live under `linters.settings`, per the v2
-  schema, so they are applied. No new lint findings surfaced (2026-08-09, branch
-  `golangci-v2.12.2`, https://git.eeqj.de/sneak/sfdupes/issues/3)
+  replaced with the canonical file. Four thresholds now live under
+  `linters.settings`, as the v2 schema requires, so they are applied:
+    - `lll`;
+    - `funlen`;
+    - `cyclop`;
+    - `dupl`.
+
+    No new lint findings surfaced (2026-08-09, branch `golangci-v2.12.2`,
+    https://git.eeqj.de/sneak/sfdupes/issues/3)
 
 - `Makefile` targets converted to scripts-to-rule-them-all `script/`
   entrypoints, like the other managed repos. All 12 entrypoints exist:
@@ -510,17 +596,17 @@ are known.
     Every `Makefile` target does nothing but call its script (2026-07-26, commit
     `3abeacf`, https://git.eeqj.de/sneak/sfdupes/issues/1)
 
-- The binary is the default `make` target: plain `make` builds `sfdupes`, where
+- The binary is the default `make` target. Plain `make` builds `sfdupes`, where
   it used to run `check` plus `build`. `make build` remains as an alias
   (2026-07-24, branch `make-default-target`)
 
 - Scan-wide phases, concurrent operands and batched updates. All operands seed
-  the shared walk pool, and every pass runs once over the whole scan, so totals
-  and ETAs are scan-global. The per-operand walk, hash and update cycles and
-  their stderr announcements are gone. The update pass commits in batched
-  transactions. The filesystem is authoritative and the database an
-  eventually-consistent reflection of it, so scan-level atomicity is not
-  required (2026-07-24, branch `scan-wide-phases`)
+  the shared walk pool, and every pass runs once over the whole scan. So the
+  totals and ETAs cover the whole scan. The per-operand walk, hash and update
+  cycles and their stderr announcements are gone. The update pass writes in
+  batches, each in its own transaction. The filesystem is authoritative and the
+  database follows it, so one scan's changes need not land all at once
+  (2026-07-24, branch `scan-wide-phases`)
 
 - The stat pass split back out of the walk. Phases are strictly sequential
   again, per operand, with parallelism only inside each phase:
@@ -530,8 +616,8 @@ are known.
     - update.
 
     The walk enumerates paths with per-directory workers, and the stat pass
-    lstats them with per-file workers, restoring the exact total and ETA of the
-    stat bar (2026-07-24, branch `parallel-phases`)
+    lstats them with per-file workers. That restores the exact total and ETA of
+    the stat bar (2026-07-24, branch `parallel-phases`)
 
 - Each operand is announced on stderr before its passes. With per-operand walk,
   hash and update cycles, a multi-operand run such as `scan /srv/*` showed pass
@@ -539,55 +625,66 @@ are known.
   `scan-operand-progress`)
 
 - Parallel walk. The walk pass was a single goroutine and took hours at about 20
-  million files on a busy pool: 22 million files in 4 hours on a ZFS server. It
-  is now a per-directory worker-pool traversal that records size and mtime
-  during the walk, folding away the separate stat pass and halving metadata I/O.
-  Each `PATH` operand commits in its own transaction, so an interrupted scan
-  keeps completed operands (2026-07-24, branch `parallel-walk`)
+  million files on a busy pool. One ZFS server took 4 hours for 22 million
+  files. It is now a walk by a pool of per-directory workers that records size
+  and mtime as it goes. That folds away the separate stat pass and halves the
+  metadata reads. Each `PATH` operand commits in its own transaction, so an
+  interrupted scan keeps completed operands (2026-07-24, branch `parallel-walk`)
 
-- Persistent scan database. `scan` maintains a SQLite database
-  (`modernc.org/sqlite`, pure Go, cgo stays disabled), keyed by absolute path,
-  that survives between runs. A rescan hashes only new or changed files, by
-  mtime and size. It deletes the records of files vanished from under the
-  scanned operands and leaves records outside them untouched, so `scan` can be
-  cronned daily. `report` and `trees` read the database, with no positional
-  arguments, instead of a scan stream. The database is at
-  `/var/lib/sfdupes/db.sqlite`, overridable via `SFDUPES_DATABASE`. WAL
+- Persistent scan database. `scan` maintains an SQLite database that survives
+  between runs, with the absolute path as each record's key. The driver is
+  `modernc.org/sqlite`, pure Go, so cgo stays disabled. A rescan hashes only new
+  or changed files, by mtime and size. It deletes the records of files vanished
+  from under the scanned operands and leaves records outside them untouched. So
+  `scan` can run daily from `cron`. `report` and `trees` read the database, with
+  no positional arguments, instead of a scan stream. The database is at
+  `/var/lib/sfdupes/db.sqlite`, and `SFDUPES_DATABASE` overrides that. WAL
   journaling plus a single-transaction update keep a report run during a scan
   safe (2026-07-24, branch `persistent-database`)
 
-- The `origin` remote (`git@git.eeqj.de:sneak/sfdupes.git`) added, `v0.0.1`
-  tagged, and `main` plus tags pushed (2026-07-23)
+- The `origin` remote, `git@git.eeqj.de:sneak/sfdupes.git`, added. `v0.0.1`
+  tagged, and `main` and the tags pushed (2026-07-23)
 
-- `scan` CLI rework. Required `PATH...` operands via cobra replace the `/srv`
-  `-root` default. The new `-x`/`--one-file-system` flag (GNU convention) stops
-  at filesystem boundaries, which are crossed by default (2026-07-23, branch
-  `scan-required-paths`)
+- `scan` command-line rework. Required `PATH...` operands, parsed by cobra,
+  replace the `/srv` `-root` default. The new `-x`, `--one-file-system` flag
+  follows the GNU convention and stops at filesystem boundaries, which the walk
+  crosses by default (2026-07-23, branch `scan-required-paths`)
 
 - The repo was brought into compliance with `REPO_POLICIES.md` (the version of
   2026-07-06), the existing repo checklist and the Go styleguide. The audit of
   2026-07-22 found these gaps, and the branch closed them:
-    - `.gitignore`, with OS, editor, Go and secrets patterns; the compiled
-      `sfdupes` binary and `files.dat` had been sitting untracked in the tree;
+    - `.gitignore`, with the standard patterns for secrets and for OS, editor
+      and Go files. The compiled `sfdupes` binary and `files.dat` had been
+      sitting untracked in the tree;
     - `.editorconfig`;
     - `LICENSE` and the README License section. MIT was assumed from house
       convention, for the owner to confirm;
     - `REPO_POLICIES.md` in the repo root;
     - the canonical `.golangci.yml`, with the 150 findings it raised fixed, so
       that `make lint` is clean;
-    - the `Makefile` targets `test`, `lint`, `fmt`, `fmt-check`, `docker` and
-      `hooks`. `check` depended on `build`, which wrote the binary, and
-      `make check` must not modify files, so `check` no longer depends on it;
+    - the `Makefile` targets the policy requires:
+        - `test` and `lint`;
+        - `fmt` and `fmt-check`;
+        - `docker` and `hooks`.
+
+        `check` depended on `build`, which wrote the binary. `make check` must
+        not modify files, so `check` no longer depends on `build`;
+
     - a test suite, which the policy required with a 30-second timeout and the
-      conditional `-v` rerun. It covers parsing, grouping, digests, suppression,
-      hashing and the scan pipeline, at 64% coverage;
-    - a multistage `Dockerfile` with hash-pinned images, a fail-fast lint stage
-      and a build stage running `make check`, plus `.dockerignore`;
+      conditional `-v` rerun. At 64% coverage, it covers:
+        - parsing and grouping;
+        - digests and suppression;
+        - hashing and the scan pipeline;
+    - a multistage `Dockerfile` and `.dockerignore`. The `Dockerfile` had:
+        - hash-pinned images;
+        - a lint stage that failed fast;
+        - a build stage that ran `make check`;
     - `.gitea/workflows/check.yml`, running `docker build .` on push with the
       checkout action pinned by commit SHA;
-    - the README sections the policy requires: a Description first line with the
-      name, purpose, category, license and author, then Getting Started,
-      Rationale, TODO, License and Author;
+    - the README sections the policy requires. The first is a Description whose
+      first line names the project, its purpose and category, its license and
+      its author. Then come Getting Started and Rationale, and at the end TODO,
+      License and Author;
     - the stale README non-goal "no git repository setup and no CI" removed;
     - the pre-commit hook, installed with `make hooks` once that target existed.
 
@@ -601,8 +698,8 @@ are known.
 
 # Future Steps
 
-- Possible later features, out of scope per README: full-content verification of
-  candidates, and helper scripts for removal.
+- Possible later features, out of scope per README, are a byte-for-byte check of
+  candidates and helper scripts for removal.
 
 # Accepted Divergences