Re-vendor the shared files from sneak/prompts at dd4027b (closes #113)

The shared files are the sneak/prompts copies at dd4027b, plus this
repository's own entries. make lint and make test each build one
Dockerfile phase without the cache, both covering the frontend; the
builder stage waits on both and takes its version from git describe
unless VERSION is given. The test phase keeps Go's module and build
caches in memory, out of the image make test tags. golangci-lint moves
to v2.14.0 with the new .golangci.yml; one test spells X-Request-ID as
canonicalheader asks. prettier formats only JavaScript, CSS, HTML and
Markdown, so .golangci.yml stays as fetched. script/fmt and
script/fmt-check put ~/.local/bin on PATH. script/bootstrap keeps a Go
only if it is exactly GO_VERSION, and re-checks the go on PATH after
installing.

Model: opus-5-5

TODO.md

@@ -22,6 +22,22 @@ Decide whether the repo moves to the layout `REPO_POLICIES.md` gives, with
 
 # Completed Steps
 
+- 2026-10-07: the files shared from `sneak/prompts` are its copies at commit
+  `dd4027b` ([#113](https://git.eeqj.de/sneak/netwatch/issues/113)), with this
+  repository's own entries after the shared content in `.gitignore`,
+  `.dockerignore` and `.editorconfig`. `make lint` and `make test` each build
+  one phase of `Dockerfile` without the cache: `lint` runs golangci-lint v2.14.0
+  over `backend/` and, through the `frontend-lint` stage, eslint; `test` runs
+  the Go tests on the Debian Go image and, through the `frontend` stage, the
+  frontend's unit tests and build. The builder stage waits on both, and without
+  a `VERSION` build argument takes the version from `git describe` on the `.git`
+  in the build context. Neither linter nor the tests run on the host for
+  `make check`; `backend/script/lint` runs the root one, and
+  `backend/.golangci.yml` is no longer checked against a sha256. prettier
+  formats only the JavaScript, CSS, HTML and Markdown, so the shared
+  `.golangci.yml` stays as fetched. `script/fmt` and `script/fmt-check` put
+  `~/.local/bin` on `PATH`, which the shared workflow no longer does.
+  `script/frontend-lint` and `script/frontend-check` are gone
 - 2026-10-07: the six Hetzner targets answer again, and failed checks are
   written to the browser console
   ([#114](https://git.eeqj.de/sneak/netwatch/issues/114)). The Hetzner