feat: 新增视频分析流水线、Web界面、孤儿清理工具；修复健壮性问题

- 新增 analysis/ 模块：MOG2活动检测、YOLO人物跟踪、MediaPipe摔倒检测、Ollama活动打标、缩略图抽取
- 新增 webapp/：Flask事件浏览界面，按需HEVC→H264转码缓存
- 新增 analyze.py：7阶段状态机流水线（scan→backfill→motion→person→fall→activity→thumbnail）
- 新增 cleanup_orphans.py：清理文件已删除的数据库孤儿记录
- 修复：motion/person/activity三阶段加单视频异常兜底，避免批次中断
- 修复：ollama_client加健康检查和3次重试，num_ctx从8192降到2048
- 修复：transcode_cache加fcntl文件锁，防止并发转码同一视频
- 修复：SQLite开WAL模式+busy_timeout，支持读写并发
- 修复：sync.py ffmpeg路径改为shutil.which查找，删除automate.py死代码PYTHON
- 修复：thumbnail失败加3次重试上限，避免无限重试损坏文件
- 新增：requirements.lock锁定版本、README文档
- 更新：.gitignore排除.playwright-mcp、截图、备份文件

requirements.lock

@@ -0,0 +1,70 @@
+absl-py==2.5.0
+annotated-types==0.8.0
+anyio==4.14.2
+blinker==1.9.0
+certifi==2026.7.22
+cffi==2.1.0
+charset-normalizer==3.4.9
+click==8.4.2
+colorama==0.4.6
+contourpy==1.3.3
+cycler==0.12.1
+filelock==3.32.0
+Flask==3.1.3
+flatbuffers==25.12.19
+fonttools==4.63.0
+frida==16.6.6
+frida-tools==12.5.1
+fsspec==2026.6.0
+h11==0.16.0
+httpcore==1.0.9
+httpx==0.28.1
+idna==3.18
+itsdangerous==2.2.0
+Jinja2==3.1.6
+kiwisolver==1.5.0
+lap==0.5.13
+MarkupSafe==3.0.3
+matplotlib==3.11.1
+mediapipe==0.10.35
+mpmath==1.3.0
+networkx==3.6.1
+numpy==1.26.4
+nvidia-ml-py==13.610.43
+ollama==0.6.2
+opencv-contrib-python==4.11.0.86
+opencv-python==4.10.0.84
+packaging==26.2
+paho-mqtt==2.1.0
+pillow==12.3.0
+polars==1.43.0
+polars-runtime-32==1.43.0
+prompt_toolkit==3.0.52
+psutil==7.2.2
+pycparser==3.0
+pycryptodome==3.23.0
+pydantic==2.13.4
+pydantic_core==2.46.4
+pyezvizapi==1.0.5.0
+Pygments==2.20.0
+pyparsing==3.3.2
+pytesseract==0.3.13
+python-dateutil==2.9.0.post0
+PyYAML==6.0.3
+requests==2.34.2
+setuptools==83.0.0
+six==1.17.0
+sounddevice==0.5.5
+sympy==1.14.0
+torch==2.13.0
+torchvision==0.28.0
+tqdm==4.69.1
+typing-inspection==0.4.2
+typing_extensions==4.16.0
+ultralytics==8.4.105
+ultralytics-thop==2.0.20
+urllib3==2.7.0
+wcwidth==0.8.2
+websockets==13.1
+Werkzeug==3.1.8
+xmltodict==1.0.4