🔀 Retitle release commits to 🚀

The release commit message is a machine-read convention (release-gate
in ci.yml skips the redundant main CI run on it), so the emoji carries
weight: change the mint in scripts/release.sh, the recognized pattern,
and both docs in one atomic commit. No tags or release commits exist
yet, so nothing historical parses differently. 🚀 matches the
gitmoji semantic (deploy/publish) better than 🔖 here.

CONTRIBUTING.md

@@ -87,7 +87,7 @@ This is why every test in the suite pairs an `expectTypeOf(...)` with an `assert
 - **Branch naming:** `feature/<desc>` / `fix/<desc>` / `chore/<desc>`
 - **Starting work:** `npm run create:branch -- <prefix>/<desc>`. It refuses, without changing anything, unless the working tree is clean (untracked files included), no merge/rebase/cherry-pick is in progress, `main` matches its upstream, and `npm run test` is green on `main` — so a later failure is always attributable to your edits. The prefix is still _your_ call, inferred from the task; the script validates it rather than guessing it.
 - **Merging:** `npm run create:finish` (on the branch). It asserts the same clean-tree / no-operation / current-`main` preconditions, fast-forwards a stale `main` (a true divergence is refused), merges the branch `--no-ff`, runs `npm run verify`, and deletes the branch only after the merge is green. The push is deliberately left to `create:release`, so the merge stays local and reviewable — read the diff yourself before finishing.
-- CI runs `npm run check` + `npm run test:ci` on every push to `main` — this is the authoritative gate. The one exception: a push headed by a release commit (`:bookmark: Release x.y.z`) skips the full `build`/`maintain` jobs, because `create:release` pushes the tag for that exact commit right after and the tag run is the authoritative one (see `release-gate` in [.gitea/workflows/ci.yml](./.gitea/workflows/ci.yml)).
+- CI runs `npm run check` + `npm run test:ci` on every push to `main` — this is the authoritative gate. The one exception: a push headed by a release commit (`:rocket: Release x.y.z`) skips the full `build`/`maintain` jobs, because `create:release` pushes the tag for that exact commit right after and the tag run is the authoritative one (see `release-gate` in [.gitea/workflows/ci.yml](./.gitea/workflows/ci.yml)).
 - **Releases are NOT triggered by pushes.** Only the maintainer triggers a release (see [Publishing workflow](#publishing-workflow)).
 
 ## Publishing workflow