feat: video analysis switched to push mode (upload whole video, sync response)

Rationale: Oracle cannot reach NAS (Tailscale userspace mode on NAS, no TUN),
the old pull+webhook design requires Edge to download video from NAS and
callback to NAS - both blocked. New design is one-way NAS -> Oracle:

- FAM-Edge: new POST /api/edge/video/push endpoint accepts multipart video
  upload, reuses existing OpenCV scene-change keyframe selection, analyzes
  synchronously and returns the result payload directly in the HTTP response
  (no webhook callback). Old /api/edge/video/analyze kept for compatibility.
- FAM-Edge: VideoPreprocessor.save_upload() saves the uploaded file
- FAM-Edge: AIOrchestrator.process_push_task() runs the full pipeline
  (health check -> extract -> select -> compress -> VLM -> fusion) and
  returns callback-style payload dict
- FAM-Core: Dispatcher rewritten to push mode - reads local video file,
  uploads with task metadata (camera_name, event_start_time from file mtime,
  known_members_context), applies the result to DB via shared
  event_receiver.apply_success_event()
- FAM-Core: event_receiver success logic extracted into reusable
  apply_success_event() (used by both webhook route and dispatcher)
- config: edge_url -> /api/edge/video/push, push_timeout 1800s, gunicorn
  Edge timeout raised to 1800s for long synchronous analysis

fam-core/config/config.yaml

@@ -1,6 +1,7 @@
 # FAM-Core 配置文件 (NAS 端) - 实际部署配置
-# Tailscale: NAS=100.70.234.39, Oracle=100.74.137.126
 # 注: Tailscale 防火墙待修复，当前 edge_url 使用 Oracle 公网 IP
+# 推送模式: NAS 上传视频到 Edge /api/edge/video/push，结果同步随响应返回，
+#          无需 Oracle 反向访问 NAS（webhook/Video-Server 拉取均不再使用）
 # Ollama 未对外暴露，chat_handler 通过 FAM-Edge 代理
 
 server:
@@ -24,12 +25,12 @@ scheduler:
 
 dispatcher:
   poll_interval: 30
-  edge_url: "http://129.146.203.203:5000/api/edge/video/analyze"
-  webhook_url: "http://100.70.234.39:8000/api/core/callback/event"
+  edge_url: "http://129.146.203.203:5000/api/edge/video/push"
   max_retries: 3
+  push_timeout: 1800
 
 video_server:
-  base_url: "http://100.70.234.39:8000/media"
+  base_url: "http://127.0.0.1:8000/media"
   token: "sentinel-media-2026"
   video_dir: "/volume1/surveillance"