REPO_POLICIES: move the example Dockerfiles into examples/

Each fenced dockerfile block moves byte for byte into its own file
under examples/, and one sentence links it where the block stood.
Phrases that pointed at a block by position now name the file. Both
checklists name the files. Rules keep their wording.

As #159 (comment) says.

Model: opus-5-5

TODO.md

@@ -34,11 +34,18 @@ fmt-check, and commit.
   stays at 88, since `golines` leaves long strings and comments as they are.
 - 2026-11-06: Compacted `prompts/REPO_POLICIES.md` from 1,145 lines and 8,427
   words to 1,066 lines and 7,812 words
+- 2026-11-09: Compacted `prompts/REPO_POLICIES.md` from 1,165 lines and 8,556
+  words to 973 lines and 7,261 words
   (https://git.eeqj.de/sneak/prompts/issues/158). Every rule keeps its meaning.
   The rules now sit under headings, the pinning rule first. Each rule that was
   stated in several places is stated once. The Makefile copies of the Go and
   Python test commands are gone, because the `Dockerfile` examples carry the
   same commands. Both checklists name the `.golangci.yml` section.
+- 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