fix(ci): use postgres service hostname for DATABASE_URL on containerized runners

Gitea act_runner runs jobs in Docker; use the services: postgres hostname, not localhost.

Co-authored-by: Cursor <cursoragent@cursor.com>

.github/workflows/ci.yml

@@ -60,9 +60,10 @@ jobs:
           --health-retries 5
         ports:
           - 5432:5432
+    # Hostname must match `services:` id. `localhost` breaks Gitea act_runner (Docker job).
     env:
-      DATABASE_URL: postgresql://postgres:postgres@localhost:5432/test
-      TEST_DATABASE_URL: postgresql://postgres:postgres@localhost:5432/test
+      DATABASE_URL: postgresql://postgres:postgres@postgres:5432/test
+      TEST_DATABASE_URL: postgresql://postgres:postgres@postgres:5432/test
     steps:
       - name: Checkout code
         uses: actions/checkout@v4