ci: add Gitea Actions workflow running the full test suite

Run tests/run_tests.py on every PR push and on push to main. The suite
uses stdlib unittest, so the workflow only needs Python; integration
tests skip cleanly when the runner has no Docker daemon reachable.

Refs: PRD 0002

Assisted-by: Claude Code

.gitea/workflows/test.yml

@@ -0,0 +1,45 @@
+# Run the project's full test suite on every PR push and on push to main.
+#
+# The suite uses stdlib `unittest` (see tests/run_tests.py) — no external
+# Python dependencies are required to execute it. Integration tests need a
+# reachable Docker daemon; if Docker is unavailable on the runner those
+# tests skip cleanly via tests/_docker.py:skip_unless_docker, so the job
+# still passes (with skips visible in the run output).
+#
+# This workflow assumes the Gitea Actions runner exposes the host Docker
+# socket to the job container so `docker` commands inside the job can
+# reach the daemon. If that's not yet configured on the runner the
+# integration tests will skip rather than fail.
+
+name: test
+
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+
+jobs:
+  test:
+    name: run tests/run_tests.py
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Set up Python
+        uses: actions/setup-python@v5
+        with:
+          python-version: "3.12"
+
+      - name: Show environment
+        run: |
+          python3 --version
+          if command -v docker >/dev/null 2>&1; then
+            docker version || true
+          else
+            echo "docker not on PATH — integration tests will skip"
+          fi
+
+      - name: Run full test suite
+        run: python3 tests/run_tests.py