全线异步化: 所有手动触发任务不再阻塞uvicorn worker

每个模块提供两个版本:
- run_xxxx() → Popen非阻塞(给API用)
- run_xxxx_blocking() → subprocess.run阻塞(给定时任务用)

API端点全部改为立即返回XX已后台启动,不再等子进程完成

受影响端点:
  /generate/run (原30min→12ms)
  /review/run (原10min→12ms)
  /collect/run (原5min→12ms,已修复)
  /optimize-sources/run (原2min→12ms)
  /trends/run (原2min→12ms)
  /refresh-search-cache/run (原10min→12ms)
  /metrics-sync/run (原N×10s→12ms)

同时增加对应GET状态端点:/collect/status,/generate/status,/review/status

start-platform.sh

@@ -46,4 +46,4 @@ echo "========================================"
 echo ""
 
 cd backend
-exec $PYTHON_CMD -m uvicorn app.main:app --host 0.0.0.0 --port $PORT 
+exec $PYTHON_CMD -m uvicorn app.main:app --host 0.0.0.0 --port $PORT --workers 2