ci: auto-fix prettier formatting in pre-commit hook and CI (#498)

Pre-commit hook:
- Stage all files modified by prettier:fix, not just src/generated/

CI (GitHub Actions):
- Add prettier-fix job that runs on PRs from the same repo
- Auto-commits formatting fixes back to the PR branch
- Skips fork PRs (no write access to fork branches)

Co-authored-by: Claude <noreply@anthropic.com>

.github/workflows/ci.yml

@@ -10,6 +10,35 @@ permissions:
   contents: read
 
 jobs:
+  prettier-fix:
+    name: Auto-fix formatting
+    if: github.event_name == 'pull_request' && github.event.pull_request.head.repo.full_name == github.repository
+    runs-on: ubuntu-latest
+    permissions:
+      contents: write
+    steps:
+      - uses: actions/checkout@v6
+        with:
+          ref: ${{ github.head_ref }}
+          token: ${{ github.token }}
+
+      - uses: actions/setup-node@v6
+        with:
+          node-version: "20"
+
+      - run: npm ci
+
+      - run: npm run prettier:fix
+
+      - name: Commit formatting changes
+        run: |
+          git diff --quiet && exit 0
+          git config user.name "github-actions[bot]"
+          git config user.email "github-actions[bot]@users.noreply.github.com"
+          git add -A
+          git commit -m "style: auto-fix prettier formatting"
+          git push
+
   build:
     strategy:
       fail-fast: false

.husky/pre-commit

@@ -17,5 +17,5 @@ fi
 npm run build:all
 npm run prettier:fix
 
-# Stage any changes to generated files (they may have been reformatted by prettier)
-git add src/generated/
+# Stage any files reformatted by prettier (generated files, source, docs, etc.)
+git diff --name-only --diff-filter=M | xargs -r git add