feat(dev): GitLab integration (@hanzo/gitlab)

Mirrors @hanzo/github for GitLab: MR review (reconstructed diff, windowed),
issue triage (labels ∩ project labels), @hanzo mentions; X-Gitlab-Token
constant-time verify; on published @hanzo/ai@0.2.0 (97 tests). CI step added.

.github/workflows/ci.yml

@@ -89,6 +89,9 @@ jobs:
     - name: Test JupyterLab extension
       run: pnpm --filter @hanzo/jupyter test
 
+    - name: Test GitLab integration
+      run: pnpm --filter @hanzo/gitlab test
+
     - name: Test cards (shared card-builder)
       run: pnpm --filter @hanzo/cards test