Add 永期半自动: human arm, machine open/close, then stop.

Settings toggle, Plan panel, Fleet monitor, exit locks and armed TOCTOU gates; docs and dual audits.

Co-authored-by: Cursor <cursoragent@cursor.com>

backend/app/main.py

@@ -47,6 +47,15 @@ async def lifespan(app: FastAPI):
     settings = load_runtime_settings()
     engine = StrategyEngine()
     set_engine(engine)
+    # 半自动：无仓时清陈旧授权，须首页重新「授权开下一单」
+    try:
+        from .strategy.semi_auto import clear_armed_if_flat
+
+        clear_armed_if_flat(
+            db, has_open_position=engine.matcher.has_open_position()
+        )
+    except Exception:
+        logger.exception("clear stale semi_armed on startup failed")
     # LIVE：进程启动后不自动真下单，须人工点「启动」
     if not get_settings().is_sim:
         try: