feat(deploy): 完成 Phase 3 优化与测试

- T-013 错误处理: 增强 API 错误处理，添加日志记录
- T-015 视频链接: 已在 ResultTable 中实现点击跳转
- T-016 部署配置: 添加前后端 Dockerfile 和 docker-compose.yml
- 新增 11 个错误处理测试用例，共 55 个测试全部通过
- 测试覆盖率达到 93%

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

backend/tests/test_error_handling.py

@@ -0,0 +1,163 @@
+import pytest
+from unittest.mock import patch, AsyncMock, MagicMock
+from httpx import AsyncClient, ASGITransport
+from sqlalchemy.exc import SQLAlchemyError
+
+from app.main import app
+from app.models import KolVideo
+from app.api.v1.export import set_export_data, get_export_data
+
+
+class TestErrorHandling:
+    """Tests for error handling scenarios."""
+
+    @pytest.fixture
+    async def client(self, override_get_db):
+        """Create test client with dependency override."""
+        transport = ASGITransport(app=app)
+        async with AsyncClient(transport=transport, base_url="http://test") as ac:
+            yield ac
+
+    @pytest.fixture
+    async def seed_data(self, test_session, sample_video_data):
+        """Seed test data."""
+        data = sample_video_data.copy()
+        data["item_id"] = "error_test_001"
+        data["star_id"] = "error_star_001"
+        video = KolVideo(**data)
+        test_session.add(video)
+        await test_session.commit()
+        return video
+
+    # Query API error handling tests
+
+    @patch("app.api.v1.query.query_videos")
+    @patch("app.api.v1.query.get_brand_names", new_callable=AsyncMock)
+    async def test_query_database_error(
+        self, mock_brand, mock_query, client
+    ):
+        """Test query returns error on database failure."""
+        mock_brand.return_value = {}
+        mock_query.side_effect = SQLAlchemyError("Database connection failed")
+
+        response = await client.post(
+            "/api/v1/query",
+            json={"type": "star_id", "values": ["test_id"]},
+        )
+        assert response.status_code == 200
+        data = response.json()
+        assert data["success"] is False
+        assert "数据库连接失败" in data["error"]
+
+    @patch("app.api.v1.query.get_brand_names", new_callable=AsyncMock)
+    async def test_query_brand_api_failure_fallback(
+        self, mock_brand, client, test_session, seed_data
+    ):
+        """Test query continues with fallback when brand API fails."""
+        mock_brand.side_effect = Exception("Brand API timeout")
+
+        response = await client.post(
+            "/api/v1/query",
+            json={"type": "star_id", "values": ["error_star_001"]},
+        )
+        assert response.status_code == 200
+        data = response.json()
+        # Should still succeed, brand name falls back to brand_id
+        assert data["success"] is True
+        assert data["total"] >= 0
+
+    @patch("app.api.v1.query.query_videos")
+    @patch("app.api.v1.query.get_brand_names", new_callable=AsyncMock)
+    async def test_query_generic_error(
+        self, mock_brand, mock_query, client
+    ):
+        """Test query returns error on unexpected exception."""
+        mock_brand.return_value = {}
+        mock_query.side_effect = Exception("Unexpected error")
+
+        response = await client.post(
+            "/api/v1/query",
+            json={"type": "star_id", "values": ["test_id"]},
+        )
+        assert response.status_code == 200
+        data = response.json()
+        assert data["success"] is False
+        assert "Unexpected error" in data["error"]
+
+    # Export API error handling tests
+
+    async def test_export_no_data_error(self, client):
+        """Test export returns error when no data is cached."""
+        # Clear cached data
+        set_export_data([])
+
+        response = await client.get("/api/v1/export?format=xlsx")
+        assert response.status_code == 400
+        data = response.json()
+        assert data["success"] is False
+        assert "无数据可导出" in data["error"]
+
+    async def test_export_with_data_success(self, client, sample_video_data):
+        """Test export succeeds when data is cached."""
+        # Set cached data
+        set_export_data([sample_video_data])
+
+        response = await client.get("/api/v1/export?format=xlsx")
+        assert response.status_code == 200
+        assert "application/vnd.openxmlformats" in response.headers["content-type"]
+
+    async def test_export_csv_with_data_success(self, client, sample_video_data):
+        """Test CSV export succeeds when data is cached."""
+        set_export_data([sample_video_data])
+
+        response = await client.get("/api/v1/export?format=csv")
+        assert response.status_code == 200
+        assert "text/csv" in response.headers["content-type"]
+
+    @patch("app.api.v1.export.generate_excel")
+    async def test_export_generation_error(
+        self, mock_generate, client, sample_video_data
+    ):
+        """Test export returns error when file generation fails."""
+        mock_generate.side_effect = Exception("Excel generation failed")
+        set_export_data([sample_video_data])
+
+        response = await client.get("/api/v1/export?format=xlsx")
+        assert response.status_code == 500
+        data = response.json()
+        assert data["success"] is False
+        assert "导出失败" in data["error"]
+
+    # Input validation tests
+
+    async def test_query_validation_empty_values(self, client):
+        """Test query returns 422 for empty values."""
+        response = await client.post(
+            "/api/v1/query",
+            json={"type": "star_id", "values": []},
+        )
+        assert response.status_code == 422
+
+    async def test_query_validation_invalid_type(self, client):
+        """Test query returns 422 for invalid query type."""
+        response = await client.post(
+            "/api/v1/query",
+            json={"type": "invalid_type", "values": ["test"]},
+        )
+        assert response.status_code == 422
+
+    async def test_query_validation_missing_type(self, client):
+        """Test query returns 422 for missing type field."""
+        response = await client.post(
+            "/api/v1/query",
+            json={"values": ["test"]},
+        )
+        assert response.status_code == 422
+
+    async def test_query_validation_missing_values(self, client):
+        """Test query returns 422 for missing values field."""
+        response = await client.post(
+            "/api/v1/query",
+            json={"type": "star_id"},
+        )
+        assert response.status_code == 422