Give the pre-commit workflow the shared-gate checkout it needs

Both delegating hooks were exiting 1 with "shared gate not found at
/home/runner/utils/scripts/...". The workflow runs `pre-commit/action` against
a bare checkout, so nothing put kuhyx/utils where the delegates look. It now
checks the shared repo out to `.utils` and points `UTILS_ROOT` at it, the same
way every other workflow in the fleet does.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01CRykabMwPgDzFHcARoqpaK

.github/workflows/pre-commit.yml

@@ -11,6 +11,18 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
+
+      # Hooks here delegate to the shared gates in kuhyx/utils. Without this
+      # checkout they exit 1 with "shared gate not found at
+      # /home/runner/utils/..." -- which is what this workflow was doing on
+      # every run since those hooks were added.
+      - name: Check out the shared gates
+        uses: actions/checkout@v4
+        with:
+          repository: kuhyx/utils
+          path: .utils
+      - name: Point the delegates at that checkout
+        run: echo "UTILS_ROOT=$GITHUB_WORKSPACE/.utils" >> "$GITHUB_ENV"
       - uses: actions/setup-python@v5
         with:
           python-version: "3.12"