ci(260613-dmw): exclude .gitea/** from heavy-job paths-filter (treat CI edits like docs)

Workflow-only edits shouldn't pay for the multi-minute MariaDB/integration/harness
suite. A negation '- !.gitea/**' (ordered after the yml/yaml globs) makes CI-config-
only PRs resolve code=false so api/harness skip like docs. fast-checks (format:check
still validates the workflow YAML) + gate continue to gate them. PRs that also touch
app code or lockfile still resolve code=true and run the full suite.

.gitea/workflows/ci.yml

@@ -29,6 +29,7 @@ jobs:
               - 'pnpm-lock.yaml'
               - 'Dockerfile'
               - 'docker-compose*.yml'
+              - '!.gitea/**'
 
   fast-checks:
     runs-on: ubuntu-latest