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

webapp/app.py

@@ -0,0 +1,106 @@
+"""本地事件展示网页：纯只读查询 analysis.db + 播放原始录像文件，
+不写入任何数据，可以在 analyze.py 跑到一半时随时启动查看已完成的部分。
+"""
+from flask import Flask, jsonify, render_template, request, send_file
+
+from analysis.config import PROJECT_ROOT
+from analysis.db import get_connection
+from webapp import transcode_cache
+
+app = Flask(__name__)
+
+EVENT_TYPES = ["person_presence", "fall", "activity"]
+
+
+@app.route("/")
+def index():
+    return render_template("index.html")
+
+
+@app.route("/api/events")
+def api_events():
+    event_type = request.args.get("event_type")
+    capture_date = request.args.get("date")  # YYYYMMDD
+
+    query = """
+        SELECT e.id, e.video_id, e.event_type, e.label, e.start_offset_sec,
+               e.end_offset_sec, e.timestamp_abs, e.confidence, e.thumbnail_path,
+               v.capture_date, v.file_name
+        FROM events e JOIN videos v ON v.id = e.video_id
+        WHERE 1=1
+    """
+    params = []
+    if event_type in EVENT_TYPES:
+        query += " AND e.event_type = ?"
+        params.append(event_type)
+    if capture_date:
+        query += " AND v.capture_date = ?"
+        params.append(capture_date)
+    query += " ORDER BY e.timestamp_abs DESC, e.id DESC LIMIT 500"
+
+    with get_connection() as conn:
+        rows = conn.execute(query, params).fetchall()
+
+    events = [
+        {
+            "id": r["id"],
+            "video_id": r["video_id"],
+            "event_type": r["event_type"],
+            "label": r["label"],
+            "start_offset_sec": r["start_offset_sec"],
+            "end_offset_sec": r["end_offset_sec"],
+            "timestamp_abs": r["timestamp_abs"],
+            "confidence": r["confidence"],
+            "capture_date": r["capture_date"],
+            "file_name": r["file_name"],
+            "thumbnail_url": f"/media/thumb/{r['id']}" if r["thumbnail_path"] else None,
+        }
+        for r in rows
+    ]
+    return jsonify(events)
+
+
+@app.route("/api/stats")
+def api_stats():
+    with get_connection() as conn:
+        rows = conn.execute(
+            "SELECT event_type, COUNT(*) AS c FROM events GROUP BY event_type"
+        ).fetchall()
+    return jsonify({r["event_type"]: r["c"] for r in rows})
+
+
+@app.route("/media/<int:video_id>/stream")
+def media_stream(video_id):
+    with get_connection() as conn:
+        row = conn.execute("SELECT file_path FROM videos WHERE id = ?", (video_id,)).fetchone()
+    if row is None:
+        return "视频不存在", 404
+
+    try:
+        play_path = transcode_cache.ensure_transcoded(video_id, PROJECT_ROOT / row["file_path"])
+    except RuntimeError as e:
+        return f"转码失败：{e}", 500
+    return send_file(play_path, conditional=True)
+
+
+@app.route("/api/cache/stats")
+def api_cache_stats():
+    return jsonify(transcode_cache.cache_stats())
+
+
+@app.route("/api/cache/clear", methods=["POST"])
+def api_cache_clear():
+    return jsonify(transcode_cache.clear_cache())
+
+
+@app.route("/media/thumb/<int:event_id>")
+def media_thumb(event_id):
+    with get_connection() as conn:
+        row = conn.execute("SELECT thumbnail_path FROM events WHERE id = ?", (event_id,)).fetchone()
+    if row is None or not row["thumbnail_path"]:
+        return "缩略图不存在", 404
+    return send_file(PROJECT_ROOT / row["thumbnail_path"], conditional=True)
+
+
+if __name__ == "__main__":
+    app.run(host="127.0.0.1", port=5050, debug=False)