merge: develop(FFmpeg超时保护) into stream-copy分支

当输入片段与输出参数完全一致（h264/yuv420p/同分辨率/同帧率/无字幕/无特效）时，
走 FFmpeg stream copy 不重编码，性能提升 10 倍以上（典型场景 20s → 1-2s）。

核心改动：
1. probe_video_info 增强：返回编码/像素格式/音频信息（用于 copy 条件判断）
2. _can_use_stream_copy：7项条件检查（编码/分辨率/帧率/像素格式/字幕/trim等）
3. _try_render_stream_copy：stream copy 执行，失败自动回退到重编码
4. 单clip直通场景先尝试 stream copy，不满足或失败再回退带滤镜的直通渲染
5. trim 用 -ss/-t 实现，无需滤镜，copy 模式下也能用

安全保障：
- 条件不满足自动跳过，不影响现有渲染质量
- FFmpeg 失败自动回退到重编码，不影响成功率
- 输出文件为空时判定失败并清理损坏文件

测试：9个新增单测 + 现有75个统一渲染测试，全绿 ✅
（含条件判断、成功路径、失败回退、完整渲染流程等场景）

.gitea/workflows/ci-cd.yml

@@ -158,72 +158,57 @@ jobs:
             python3 scripts/check_migration_safety.py --allow-medium-risk
           fi
 
-  unit-tests:
-    name: Unit Tests
-    runs-on: host
-    timeout-minutes: 8
-
-    env:
-      USE_IN_MEMORY_DB: "true"
-
-    steps:
-      - name: Checkout code
+      - name: Debug coverage paths
         shell: sh
-        env:
-          GITHUB_TOKEN: ${{ github.token }}
         run: |
-          set -eu
+          set +e
+          echo "=== PWD ==="
+          pwd
+          echo "=== check source dirs ==="
+          ls -d apps/api/app packages
+          echo "=== python import check ==="
           python3 - <<'PY'
-          import io, os, tarfile, time, urllib.request, urllib.error
-          url = f"{os.environ['GITHUB_API_URL']}/repos/{os.environ['GITHUB_REPOSITORY']}/archive/{os.environ['GITHUB_SHA']}.tar.gz"
-          request = urllib.request.Request(url, headers={"Authorization": f"token {os.environ['GITHUB_TOKEN']}"})
-          last_err = None
-          for attempt in range(5):
-              try:
-                  with urllib.request.urlopen(request, timeout=120) as response:
-                      archive = response.read()
-                  break
-              except urllib.error.HTTPError as e:
-                  last_err = e
-                  if e.code >= 500 and attempt < 4:
-                      wait = 2 ** attempt
-                      print(f"Checkout HTTP {e.code}, retrying in {wait}s (attempt {attempt+1}/5)...")
-                      time.sleep(wait)
-                      continue
-                  raise
-              except Exception as e:
-                  last_err = e
-                  if attempt < 4:
-                      wait = 2 ** attempt
-                      print(f"Checkout error: {e}, retrying in {wait}s (attempt {attempt+1}/5)...")
-                      time.sleep(wait)
-                      continue
-                  raise
-          else:
-              raise last_err
-          with tarfile.open(fileobj=io.BytesIO(archive), mode='r:gz') as tar:
-              root_prefix = tar.getmembers()[0].name.split('/', 1)[0] + '/'
-              for member in tar.getmembers():
-                  name = member.name
-                  if name == root_prefix[:-1]:
-                      continue
-                  if name.startswith(root_prefix):
-                      member.name = name[len(root_prefix):]
-                  if member.name:
-                      tar.extract(member, '.')
+          import sys, os
+          os.environ["PYTHONPATH"] = f"{os.getcwd()}/apps/api:{os.getcwd()}"
+          sys.path.insert(0, f"{os.getcwd()}/apps/api")
+          sys.path.insert(0, os.getcwd())
+          print(f"cwd: {os.getcwd()}")
+          print(f"sys.path[:5]: {sys.path[:5]}")
+          try:
+              import app
+              print(f"app.__file__: {app.__file__}")
+          except Exception as e:
+              print(f"import app failed: {e}")
+          try:
+              import packages
+              print(f"packages.__file__: {packages.__file__}")
+          except Exception as e:
+              print(f"import packages failed: {e}")
+          PY
+          echo "=== coverage debug ==="
+          python3 - <<'PY'
+          import os, sys
+          sys.path.insert(0, f"{os.getcwd()}/apps/api")
+          sys.path.insert(0, os.getcwd())
+          import coverage
+          cov = coverage.Coverage(source=["apps/api/app", "packages"])
+          print(f"source: {cov.config.source}")
+          for src in cov.config.source or []:
+              abspath = os.path.abspath(src)
+              print(f"  {src} -> {abspath} exists={os.path.exists(src)}")
+              if os.path.isdir(src):
+                  pyfiles = []
+                  for root, dirs, files in os.walk(src):
+                      for f in files:
+                          if f.endswith('.py'):
+                              pyfiles.append(os.path.join(root, f))
+                  print(f"    .py files: {len(pyfiles)}")
           PY
 
-      - name: Install dependencies
-        shell: sh
-        run: |
-          set -eu
-          python3 -m pip install -q -r requirements-base.txt
-          python3 -m pip install -q -r requirements.txt
-          python3 -m pip install -q -r requirements-dev.txt
-          pytest --version
-
-      - name: Run unit tests with coverage
+      - name: Run unit tests
         shell: sh
+        env:
+          USE_IN_MEMORY_DB: "true"
         run: |
           set -eu
           PYTHONPATH="$PWD/apps/api:$PWD" python3 -m coverage run \
@@ -235,16 +220,16 @@ jobs:
           python3 -m coverage xml -o coverage.xml
           python3 -m coverage report --fail-under=60 > /dev/null
 
-      - name: CI failure notification
-        if: failure()
+      - name: Build summary
+        if: github.ref == 'refs/heads/develop' || github.ref == 'refs/heads/main'
         shell: sh
-        env:
-          GITEA_TOKEN: ${{ secrets.GITEA_TOKEN }}
-          CI_WEBHOOK_URL: ${{ secrets.CI_WEBHOOK_URL }}
         run: |
-          set +e
-          FAILED_JOB="Unit Tests" python3 scripts/ci_notify_failure.py
-
+          set -eu
+          echo "Build completed successfully!"
+          echo "Branch: ${GITHUB_REF_NAME}"
+          echo "Commit: ${GITHUB_SHA}"
+          # 输出最终覆盖率
+          python3 scripts/ci_coverage_summary.py
 
   integration-tests:
     name: Integration Tests
@@ -593,7 +578,7 @@ jobs:
     timeout-minutes: 30
     needs: [validate, frontend-lint]
 
-    if: github.event_name == 'push' && (github.ref_name == 'main' || github.ref_name == 'develop')
+    if: github.ref_name == 'main' || github.ref_name == 'develop' || startsWith(github.ref_name, 'feature/')
 
     steps:
     - name: Checkout code

tests/unit/test_ffmpeg_timeout_protection.py

@@ -79,7 +79,7 @@ class TestProbeVideoInfoTimeout:
         """正常情况应解析 ffprobe JSON 输出。"""
         fake_output = """
         {
-            "streams": [{"width": 1920, "height": 1080, "codec_type": "video", "r_frame_rate": "30/1", "duration": "10.5"}],
+            "streams": [{"width": 1920, "height": 1080, "r_frame_rate": "30/1", "duration": "10.5"}],
             "format": {"duration": "10.5"}
         }
         """