chore: re-vendor canonical files from prompts at dd4027b (closes #472)

Copies .dockerignore, .gitignore, .prettierignore, check.yml and
REPO_POLICIES.md from sneak/prompts at dd4027b, keeping the repo's own
entries (dist/, release/, yarn files) after the canonical content.

The Dockerfile gets separate lint and test phases; its last stage
depends on both, checks the git describe version and runs make build.
script/lint, test, check, cibuild and docker are the canonical models.
check-censored moves into the lint phase and test-verify-build into the
test phase. fmt and fmt-check fall back to the nvm-installed node. The
e2e image builds are uncached. Comments citing the old test caps or what
runs a script are updated.

Model: opus-5-5

TODO.md

@@ -45,6 +45,19 @@ but the review is broader than any of them.
 
 # Completed Steps
 
+- 2026-10-06: The canonical files are re-vendored from `sneak/prompts` at
+  `dd4027b` ([#472](https://git.eeqj.de/sneak/AutistMask/issues/472)). The
+  `Dockerfile` has separate `lint` and `test` phases, and its last stage depends
+  on both before it runs `make build`. `script/lint` and `script/test` each
+  build one phase, uncached. `script/check-censored` runs in the `lint` phase
+  and `script/test-verify-build` in the `test` phase. `script/check` runs the
+  two phases and `script/fmt-check`. `script/cibuild` bootstraps, runs
+  `script/check`, then builds the image uncached. Given no `VERSION` build
+  argument, as in a plain `docker build .`, the image build takes one from
+  `git describe` on the `.git` in the build context, which `.dockerignore` now
+  sends without its `config`. The vendored `check.yml` has no `timeout-minutes`,
+  so the `check` job's cap is gone.
+
 - 2026-10-06: Reloading or closing the popup mid-refresh no longer logs the
   requests that cancels as failures
   ([#218](https://git.eeqj.de/sneak/AutistMask/issues/218)). Chrome cancels a