🧪 test: add official Gitea Actions demo workflow

.gitea/workflows/test-trigger.yaml

@@ -0,0 +1,11 @@
+name: Test Trigger
+
+on:
+  push:
+    branches: [main]
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    steps:
+      - run: echo "Hello World from Gitea Actions"