ci: migrate commit linting

.githooks/commit-msg

@@ -2,4 +2,6 @@
 set -euo pipefail
 
 repo_root="$(git rev-parse --show-toplevel)"
-"$repo_root/scripts/check-conventional-commits.sh" --message-file "$1"
+cd "$repo_root"
+
+git stripspace --strip-comments < "$1" | npm run --silent lint:commit --

.github/workflows/ci.yml

@@ -29,6 +29,14 @@ jobs:
         with:
           fetch-depth: 0
 
+      - uses: actions/setup-node@v4
+        with:
+          node-version: 22
+          cache: npm
+
+      - name: Install commit message lint dependencies
+        run: npm ci
+
       - name: Reject tracked ignored files
         run: scripts/check-release-pr-integrity.sh HEAD HEAD
 
@@ -37,7 +45,7 @@ jobs:
         env:
           BASE_SHA: ${{ github.event.pull_request.base.sha }}
           HEAD_SHA: ${{ github.event.pull_request.head.sha }}
-        run: scripts/check-conventional-commits.sh "$BASE_SHA..$HEAD_SHA"
+        run: npm run lint:commit -- --from "$BASE_SHA" --to "$HEAD_SHA"
 
       - name: Validate pushed commit messages
         if: github.event_name == 'push'
@@ -48,14 +56,13 @@ jobs:
           set -euo pipefail
           if [ "$BEFORE_SHA" = "0000000000000000000000000000000000000000" ]; then
             if git rev-parse "${HEAD_SHA}^" >/dev/null 2>&1; then
-              RANGE="${HEAD_SHA}^..${HEAD_SHA}"
+              npm run lint:commit -- --from "${HEAD_SHA}^" --to "$HEAD_SHA"
             else
-              RANGE="$HEAD_SHA"
+              git show --no-patch --format=%B "$HEAD_SHA" | npm run lint:commit --
             fi
           else
-            RANGE="${BEFORE_SHA}..${HEAD_SHA}"
+            npm run lint:commit -- --from "$BEFORE_SHA" --to "$HEAD_SHA"
           fi
-          scripts/check-conventional-commits.sh "$RANGE"
 
   release-version-drift:
     name: Release Version Drift

.gitignore

@@ -1,4 +1,5 @@
 /target
+/node_modules/
 .DS_Store
 .codegraph
 .tracedecay

AGENTS.md

@@ -35,7 +35,8 @@ cargo test-all
 
 ## Git
 
-- Every non-merge commit subject must pass `scripts/check-conventional-commits.sh` before push.
+- Every non-merge commit subject must pass
+  `npm run lint:commit -- --from origin/master --to HEAD` before push.
 - Use `<type>: <subject>` or `<type>(<scope>): <subject>` with one of:
   `build`, `chore`, `ci`, `docs`, `feat`, `fix`, `perf`, `refactor`, `revert`, `style`, `test`.
 - Keep the subject at 72 characters or fewer. Example: `fix(doctor): avoid false orphan warnings`.

CONTRIBUTING.md

@@ -160,11 +160,12 @@ scripts/install-git-hooks.sh
 CI validates commit subjects with:
 
 ```bash
-scripts/check-conventional-commits.sh origin/master..HEAD
+npm ci
+npm run lint:commit -- --from origin/master --to HEAD
 ```
 
 Run the same command locally before pushing to lint every non-merge commit in a
-branch range. Merge commits are skipped to match CI behavior.
+branch range. Commitlint exempts merge commits to match CI behavior.
 
 ## Pull Requests
 

commitlint.config.cjs

@@ -0,0 +1,32 @@
+const allowedTypes = [
+  "build",
+  "chore",
+  "ci",
+  "docs",
+  "feat",
+  "fix",
+  "perf",
+  "refactor",
+  "revert",
+  "style",
+  "test",
+];
+
+module.exports = {
+  defaultIgnores: false,
+  ignores: [(message) => /^Merge[ \t]/.test(message)],
+  parserPreset: {
+    name: "tracedecay",
+    parserOpts: {
+      headerCorrespondence: ["type", "scope", "breaking", "subject"],
+      headerPattern:
+        /^(\w*)(?:\(([A-Za-z0-9._/-]+)\))?(!)?: ([^\s].*)$/,
+    },
+  },
+  rules: {
+    "header-max-length": [2, "always", 72],
+    "subject-empty": [2, "never"],
+    "type-empty": [2, "never"],
+    "type-enum": [2, "always", allowedTypes],
+  },
+};