Add per-symbol close position and clear orders actions to demo trading

The API queues the request in Redis and the executor applies it on its
next pass, so it never races reconciliation. Both actions cancel every
open order on the symbol, including manual ones, and market-close any
position. Plans end as manual_close or manual_cancel without queueing
a new analysis. Closing also stops trading so the engine does not
reopen right away.

backend/src/alphapulse/api/trading.py

@@ -19,6 +19,7 @@ from alphapulse.core.db import get_session
 from alphapulse.core.redis import KEY_PREFIX, redis
 from alphapulse.models import AiProvider, TradingAccount, TradingAnalysis, TradingEvent, TradingFill, TradingOrder, TradingSymbol
 from alphapulse.trading.client import OWN_CLIENT_ID, ExchangeError, public_get
+from alphapulse.trading.executor import MANUAL_ACTION_KEY
 from alphapulse.trading.positions import build_positions
 from alphapulse.trading.plan import DAILY_ANALYSIS_LIMIT
 from alphapulse.trading.snapshot import read_snapshot
@@ -29,6 +30,8 @@ SYMBOLS_CACHE_KEY = f"{KEY_PREFIX}trading:symbols"
 SYMBOLS_CACHE_SECONDS = 3600
 # 删除前要求快照足够新，否则无法确认没有仓位和挂单
 SNAPSHOT_FRESH_SECONDS = 30
+# 平仓、清除挂单的请求等执行器取走的时限：引擎没及时处理就作废，不在之后意外执行
+MANUAL_ACTION_TTL_SECONDS = 30
 # 执行器正在管理的计划状态
 LIVE_PLAN_STATUSES = ("pending", "open", "closing")
 
@@ -312,6 +315,15 @@ async def add_symbol(body: SymbolIn, session: Annotated[AsyncSession, Depends(ge
         raise HTTPException(status.HTTP_409_CONFLICT, f"{symbol} 已在交易列表中") from None
 
 
+async def fresh_snapshot(symbol: str, action: str) -> dict:
+    """引擎在线且刚和币安同步过的快照"""
+    snapshot = await read_snapshot()
+    synced_at = snapshot and snapshot["synced_at"] and datetime.fromisoformat(snapshot["synced_at"])
+    if not synced_at or datetime.now(LOCAL_TZ) - synced_at > timedelta(seconds=SNAPSHOT_FRESH_SECONDS):
+        raise HTTPException(status.HTTP_409_CONFLICT, f"无法确认 {symbol} 的仓位和挂单（引擎离线或连接币安失败），暂时不能{action}")
+    return snapshot
+
+
 async def ensure_idle(session: AsyncSession, symbol: str, action: str) -> TradingSymbol:
     """只有空仓、没有本程序的挂单、没有进行中的计划和分析时，才能删除"""
     s = await session.get(TradingSymbol, symbol)
@@ -323,10 +335,7 @@ async def ensure_idle(session: AsyncSession, symbol: str, action: str) -> Tradin
     ))
     if busy:
         raise HTTPException(status.HTTP_409_CONFLICT, f"{symbol} 有进行中的分析或计划，不能{action}")
-    snapshot = await read_snapshot()
-    synced_at = snapshot and snapshot["synced_at"] and datetime.fromisoformat(snapshot["synced_at"])
-    if not synced_at or datetime.now(LOCAL_TZ) - synced_at > timedelta(seconds=SNAPSHOT_FRESH_SECONDS):
-        raise HTTPException(status.HTTP_409_CONFLICT, f"无法确认 {symbol} 的仓位和挂单（引擎离线或连接币安失败），暂时不能{action}")
+    snapshot = await fresh_snapshot(symbol, action)
     if any(p["symbol"] == symbol for p in snapshot["positions"]):
         raise HTTPException(status.HTTP_409_CONFLICT, f"{symbol} 有持仓，不能{action}")
     if any(o["symbol"] == symbol and OWN_CLIENT_ID.match(o["client_id"]) for o in snapshot["orders"] + snapshot["algo_orders"]):
@@ -343,6 +352,19 @@ async def delete_symbol(symbol: str, session: Annotated[AsyncSession, Depends(ge
     await session.commit()
 
 
+@router.post("/symbols/{symbol}/manual/{action}", status_code=status.HTTP_202_ACCEPTED)
+async def manual_action(symbol: str, action: Literal["close", "cancel"], session: Annotated[AsyncSession, Depends(get_session)]) -> None:
+    """一键平仓（同时停止行情交易）、清除挂单：交给执行器执行，结果写入时间线"""
+    label = "平仓" if action == "close" else "清除挂单"
+    if await session.get(TradingSymbol, symbol) is None:
+        raise HTTPException(status.HTTP_404_NOT_FOUND, f"{symbol} 不在交易列表中")
+    await fresh_snapshot(symbol, label)
+    if action == "close":
+        # 不停止的话，平仓后会重新分析，可能马上又开仓
+        await set_running(session, False)
+    await redis.set(MANUAL_ACTION_KEY.format(symbol), action, ex=MANUAL_ACTION_TTL_SECONDS)
+
+
 @router.get("/events")
 async def list_events(
     session: Annotated[AsyncSession, Depends(get_session)],