Run only script/cibuild in the Gitea workflow (closes #203)

The workflow's script/docker-smoke step is removed, so the workflow
checks out the repo and runs script/cibuild and nothing else, as the
canonical REPO_POLICIES.md says. The owner ruled on the issue that
make check covers what needs covering.

CI no longer starts the image and waits for its healthcheck.
script/docker-smoke and make docker-smoke stay, to run by hand, and
the script's header comment no longer says the workflow runs it. The
dated TODO.md entries that say the workflow runs it are history and
stay as written.

Model: opus-5-5

TODO.md

@@ -30,6 +30,11 @@ P2: security: per-origin rate limiting
 
 # Completed Steps
 
+- 2026-10-21 the Gitea workflow checks out the repo and runs `script/cibuild`,
+  nothing else (closes #203): its `script/docker-smoke` step is removed, as the
+  canonical `REPO_POLICIES.md` says, since `make check` covers what CI needs to
+  check. CI no longer starts the image and waits for its healthcheck.
+  `script/docker-smoke` and `make docker-smoke` stay, to run by hand.
 - 2026-10-20 a WebP, AVIF or JPEG XL encode at the limits takes at most about 34
   seconds (closes #272): with one libvips thread, 8192x8192 random pixels with
   an alpha channel took about 61 seconds to encode as WebP, 81 as JPEG XL and,