cibuild: the org model, which runs every check uncached (closes #37)

script/cibuild was a plain docker build ., so on a tree Docker had
seen before every check step came from the build cache and the build
still passed. It is now the org model from sneak/prompts, byte for
byte: script/bootstrap, script/check, then docker build --no-cache
with the git describe version as the VERSION build argument.

The workflow puts ~/.local/bin, where bootstrap links what it
installs, on the step's PATH. Bootstrap now installs its pinned node
when the installed one is older than 22.12.0, the oldest the
frontend's dependencies accept (puppeteer-core's engines field), as
it already does for Go against backend/go.mod.

Model: opus-5-5

TODO.md

@@ -23,6 +23,14 @@ latest run passes.
 
 # Completed Steps
 
+- 2026-09-29: CI can no longer pass on checks that did not run (issue #37):
+  `script/cibuild` is now the org model, byte for byte. It runs
+  `script/bootstrap` and `script/check`, then builds the image with `--no-cache`
+  and the version from `git describe` as the `VERSION` build argument, where it
+  used to be a plain `docker build .` whose check steps could come from the
+  build cache. The workflow puts `~/.local/bin`, where bootstrap links what it
+  installs, on the step's `PATH`, and bootstrap now installs its pinned node
+  when the installed one is older than the frontend's dependencies need
 - 2026-09-29: `backend/.golangci.yml` re-vendored from `sneak/prompts` (issue
   #41): `gomodguard`, deprecated in golangci-lint v2.12.0, is disabled and its
   successor `gomodguard_v2` enabled with the org block list, so lint runs print