Commit yarn 4 in the tree and install with --immutable (closes #149)

Follows sneak's ruling at
#149 (comment). This
repository now carries yarn 4.18.1 under .yarn/releases. The
distribution's yarn only starts that file, and that file does the work.
yarn.lock is converted once, and script/bootstrap installs with
--immutable instead of stopping on yarn's major version. Node is the
distribution's newest Node package: nodejs-current on Alpine and
nodejs_latest on nix. Every Dockerfile stage that needs yarn also copies
.yarnrc.yml and .yarn/releases/. The policies and both checklists say
so, with the steps for converting and for a new repository.

Model: opus-5-5

TODO.md

@@ -21,16 +21,6 @@ fmt-check, and commit.
 
 # Completed Steps
 
-- 2026-11-07: Go code is now formatted with `gofmt` and then `golines -m 77`
-  (https://git.eeqj.de/sneak/prompts/issues/160). `prompts/REPO_POLICIES.md`
-  says how `script/fmt`, `script/fmt-check` and `script/bootstrap` do it and
-  pins `golines`. The Go style guide and both checklists say the same. `lll`
-  stays at 88, since `golines` leaves long strings and comments as they are.
-- 2026-11-06: The pinning rule in `prompts/REPO_POLICIES.md` now opens with its
-  scope: what we download and install ourselves in scripts and Dockerfiles
-  (https://git.eeqj.de/sneak/prompts/issues/154). Distribution packages are
-  outside the rule, and updating and upgrading them is allowed. Both checklists
-  say the same.
 - 2026-11-04: Each repository now commits yarn 4 and installs with
   `yarn install --immutable` (https://git.eeqj.de/sneak/prompts/issues/149), on
   sneak's ruling at

prompts/CODE_STYLEGUIDE_GO.md

@@ -1,16 +1,13 @@
 ---
 title: Code Styleguide — Go
-last_modified: 2026-11-07
+last_modified: 2026-10-18
 ---
 
-1.  Format Go code with `gofmt` and then `golines -m 77`, through `make fmt`.
+1.  Try to hard wrap long lines at 77 characters or less.
-    Don't commit anything `make fmt` would change. The only exception is when
-    committing things that aren't yet syntactically valid, which should only
-    happen pre-v0.0.1 or on a non-`main` branch.
 
-1.  Hard wrap long lines at 77 characters or less. `golines` does this for code.
+1.  Don't commit anything that hasn't been `go fmt`'d. The only exception is
-    Wrap comments and long string literals by hand, since `golines` leaves them
+    when committing things that aren't yet syntactically valid, which should
-    as they are.
+    only happen pre-v0.0.1 or on a non-`main` branch.
 
 1.  Even if you are planning to deal with only positive integers, use
     `int`/`int64` types instead of `uint`/`uint64` types. This is for

prompts/EXISTING_REPO_CHECKLIST.md

@@ -1,6 +1,6 @@
 ---
 title: Existing Repo Checklist
-last_modified: 2026-11-07
+last_modified: 2026-11-04
 ---
 
 Use this checklist when beginning work in a repo that may not yet conform to our
@@ -259,27 +259,22 @@ with your task.
 
 # Formatting
 
-- [ ] Platform-standard formatter is configured (`black`, `prettier`, and for Go
+- [ ] Platform-standard formatter is configured (`black`, `prettier`, `go fmt`)
-      `gofmt` then `golines -m 77`)
+- [ ] Default formatter config, only exception: four-space indents (except Go)
-- [ ] Default formatter config, except four-space indents (not Go),
-      `proseWrap: always` for Markdown, and the Go 77-column limit
-- [ ] Go: `script/bootstrap` installs `golines` with `go install` pinned to a
-      commit hash; `script/fmt-check` fails when `gofmt` or `golines -m 77`
-      would change a file
 - [ ] All files pass `make fmt-check`
 
 # Git Hygiene
 
 - [ ] Pre-commit hook is installed (`make hooks`)
 - [ ] No secrets in the repo (`.env`, keys, credentials)
-- [ ] No mutable references (tags, `@latest`) to what the repo downloads and
+- [ ] No mutable references in Dockerfiles or scripts (tags, `@latest`) — all
-      installs itself in scripts and Dockerfiles — all pinned by cryptographic
+      pinned by cryptographic hash with version/date comment. The one exception
-      hash with version/date comment. Distribution packages are outside this
+      is a package from the distribution's own package index, which needs no
-      rule. They need no version and no hash, and updating and upgrading them is
+      version and no hash. Pulling that index is also allowed. In a
-      fine too. In a `Dockerfile`, the distribution is the pinned base image's.
+      `Dockerfile`, the distribution is the pinned base image's. On a host, it
-      On a host, it is the host's, and the host's package manager stands for it,
+      is the host's, and the host's package manager stands for it, nix and brew
-      nix and brew included. A package source that a `Dockerfile` adds itself is
+      included. A package source that a `Dockerfile` adds itself does not get
-      not the distribution's own, so its packages are pinned
+      this exception
 - [ ] node, yarn, npm, python, pip and venv come from the distribution wherever
       possible, never from nvm, pyenv, corepack or `npm install -g yarn`. If the
       distribution's version is too old, use a newer distribution. node means

prompts/NEW_REPO_CHECKLIST.md

@@ -1,6 +1,6 @@
 ---
 title: New Repo Checklist
-last_modified: 2026-11-07
+last_modified: 2026-11-04
 ---
 
 Use this checklist when creating a new repository from scratch. Follow the steps
@@ -233,11 +233,9 @@ are thin shims calling them. Model scripts:
       which writes no image. No lint verdict may come from a host invocation of
       the linter.
 - [ ] `script/fmt` / `make fmt` — formats code (writes; native, never in a
-      container). Go code gets `gofmt`, then `golines -m 77`.
+      container)
 - [ ] `script/fmt-check` / `make fmt-check` — checks formatting (read-only;
-      native). Fails when `gofmt` or `golines -m 77` would change a Go file.
+      native)
-- [ ] Go: `script/bootstrap` installs `golines` with `go install` pinned to a
-      commit hash
 - [ ] `script/check` / `make check` — runs `test`, `lint`, `fmt-check`; must not
       modify files
 - [ ] `script/projectname` — outputs the project name (used by `script/docker`
@@ -287,13 +285,12 @@ are thin shims calling them. Model scripts:
       final stage is missing its `COPY --from=` edge to the gate phases.
 - [ ] No secrets in repo, and none in the build context: enumerate a probe image
       rather than reading `.dockerignore`
-- [ ] No mutable references to what the repo downloads and installs itself in
+- [ ] No mutable image/package references. The one exception is a package from
-      scripts and Dockerfiles. Distribution packages are outside this rule. They
+      the distribution's own package index, which needs no version and no hash.
-      need no version and no hash, and updating and upgrading them is fine too.
+      Pulling that index is also allowed. In a `Dockerfile`, the distribution is
-      In a `Dockerfile`, the distribution is the pinned base image's. On a host,
+      the pinned base image's. On a host, it is the host's, and the host's
-      it is the host's, and the host's package manager stands for it, nix and
+      package manager stands for it, nix and brew included. A package source
-      brew included. A package source that a `Dockerfile` adds itself is not the
+      that a `Dockerfile` adds itself does not get this exception
-      distribution's own, so its packages are pinned
 - [ ] node, yarn, npm, python, pip and venv come from the distribution wherever
       possible, never from nvm, pyenv, corepack or `npm install -g yarn`. If the
       distribution's version is too old, use a newer distribution. node means

prompts/REPO_POLICIES.md

@@ -1,6 +1,6 @@
 ---
 title: Repository Policies
-last_modified: 2026-11-07
+last_modified: 2026-11-04
 ---
 
 This document covers repository structure, tooling, and workflow standards. Code
@@ -21,28 +21,13 @@ style conventions are in separate documents:
   with the authoritative source as policies evolve.
 
 - **External references must be pinned by cryptographic hash.** This is the
-  single most important rule in this document. It covers what we download and
+  single most important rule in this document. It covers everything fetched from
-  install ourselves in scripts and Dockerfiles:
+  a remote source, including:
     - Docker base images
     - Go modules
-    - Python packages from PyPI
+    - Python packages
     - npm packages
     - GitHub Actions
-    - release archives fetched with `curl` or `wget`
-
-    Packages from the distribution's own package manager are outside this rule.
-    They need no version and no hash, because the distribution is trusted. In a
-    `Dockerfile`, it is the pinned base image's distribution. On a host, it is
-    the host's. The host's package manager stands for its distribution, and that
-    includes nix and brew. Updating the package index and upgrading installed
-    packages are fine too. This command, for example, is allowed:
-
-    ```sh
-    apt update && apt upgrade -y && apt install -y build-essential
-    ```
-
-    A package source that a `Dockerfile` adds itself is not the distribution's
-    own, so its packages are pinned like any other download.
 
     A version tag such as `@v4`, `@latest` or `:3.21` is server-mutable, and
     therefore a remote code execution vulnerability. Reference an external
@@ -59,6 +44,17 @@ style conventions are in separate documents:
     Unverified install scripts are arbitrary remote code execution. Double-check
     every external reference in every file before committing.
 
+    There is one exception: a package from the distribution's own package index
+    needs no version and no hash. Pulling that index is also allowed. The
+    distribution is trusted. In a `Dockerfile`, it is the pinned base image's
+    distribution. On a host, it is the host's. The host's package manager stands
+    for its distribution, and that includes nix and brew. These commands are
+    examples:
+    - `apt-get update`
+    - `apt-get install`
+    - `apk update`
+    - `apk add`
+
     These come from the distribution wherever possible:
     - node, meaning the distribution's newest Node package, such as
       `nodejs-current` on Alpine 3.24
@@ -83,6 +79,9 @@ style conventions are in separate documents:
     - the npm registry
     - `go get`
 
+    A package source that a `Dockerfile` adds itself is not the distribution's
+    own, so the exception does not cover it.
+
 - Every repo with software must have a root `Makefile` with these targets:
     - `make bootstrap`
     - `make setup`
@@ -200,15 +199,14 @@ style conventions are in separate documents:
     README must document the provided scripts in an **Entrypoints** section (see
     the README requirements below).
 
-- Run the repo's own entrypoints, never the underlying tools directly. The
+- Always use Makefile targets (`make fmt`, `make test`, `make lint`, etc.)
-  `script/` scripts are the single source of truth for how each operation runs.
+  instead of invoking the underlying tools directly. The Makefile is the single
-  Calling them directly is fine, and so is calling the Makefile targets. The
+  source of truth for how these operations are run.
-  Makefile targets must still exist, as the thin shims described above.
 
     An agent whose work is confined to one package may run `go test` directly on
     that package's suite, or on individual tests in it, while iterating. This is
     the only exception to this rule. `go build`, `go vet` and the linter still
-    go through the entrypoints. A run while iterating is not a gate, so the full
+    go through make targets. A run while iterating is not a gate, so the full
     `make check` is still required before every push.
 
 - The Makefile is authoritative documentation for how the repo is used. Beyond
@@ -675,31 +673,11 @@ style conventions are in separate documents:
 - Use platform-standard formatters:
     - `black` for Python
     - `prettier` for JS/CSS/Markdown/HTML
-    - `gofmt`, then `golines -m 77`, for Go
+    - `go fmt` for Go
 
-    Always use default configuration, with three exceptions:
+    Always use default configuration, with two exceptions:
     - four-space indents (except Go)
     - `proseWrap: always` for Markdown (hard-wrap at 80 columns)
-    - a 77-column limit for Go, set by `golines -m 77`
-
-    `script/fmt` runs `gofmt` and then `golines -m 77` on Go code.
-    `script/fmt-check` fails when either of them would change a file. `golines`
-    comes from `github.com/segmentio/golines`. `script/bootstrap` installs it
-    with `go install`, pinned to a commit hash as below:
-
-    ```sh
-    # golines v0.13.0, 2025-08-21
-    go install github.com/segmentio/golines@8f32f0f7e89c30f572c7f2cd3b2a48016b9d8bbf
-    ```
-
-    `script/bootstrap` reads the installed version from the `mod` line of
-    `go version -m "$(command -v golines)"`, which reports `v0.13.0`. It does
-    not use `golines --version`, which prints `golines vdev` for a binary that
-    `go install` built.
-
-    `golines` cannot shorten every line: long string literals and comments stay
-    as they are. golangci-lint's `lll` limit therefore stays at 88 columns, so
-    it fails only lines far past the formatter's limit.
 
     Documentation and writing repos (Markdown, HTML, CSS) should also have
     `.prettierrc` and `.prettierignore`.