feat: Phase 3 — web dashboard, testing, and CI/CD

- Remove multi-marketplace from Phase 3
- Add FastAPI web UI on port 8766 with basic auth
- Add 6 Jinja2 templates (dashboard, keywords, users, ads, stats)
- Add pytest test suite (45 tests, 49% coverage)
- Add GitHub Actions CI/CD workflow
- Update docker-compose.yml to expose web UI port
- Update Dockerfile to include tests

worker/tests/test_health.py

@@ -0,0 +1,29 @@
+"""Tests for health module."""
+
+from health import create_health_app
+
+
+class TestHealthModule:
+    """Basic import and app creation tests for the health module."""
+
+    def test_health_module_import(self):
+        """Health module should be importable."""
+        import health
+        assert health is not None
+
+    def test_create_health_app_returns_app(self):
+        """create_health_app should return an aiohttp web.Application."""
+        app = create_health_app()
+        assert app is not None
+        assert hasattr(app, "router")
+
+    def test_health_app_has_routes(self):
+        """Health app should have /health and /stats routes."""
+        app = create_health_app()
+        # Collect route info from the router
+        routes_info = []
+        for route in app.router.routes():
+            routes_info.append(repr(route))
+        routes_str = " ".join(routes_info)
+        assert "/health" in routes_str
+        assert "/stats" in routes_str