Implement P1 local matcher/ledger and P2 strategy engine.

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

backend/app/api/plan.py

@@ -0,0 +1,30 @@
+from __future__ import annotations
+
+from typing import Annotated
+
+from fastapi import APIRouter, Depends
+
+from ..strategy import get_engine
+from .auth import require_user
+
+router = APIRouter(prefix="/api/plan", tags=["plan"])
+
+
+@router.get("/state")
+async def plan_state(_user: Annotated[str, Depends(require_user)]) -> dict:
+    return get_engine().state()
+
+
+@router.post("/start")
+async def plan_start(_user: Annotated[str, Depends(require_user)]) -> dict:
+    return await get_engine().start()
+
+
+@router.post("/pause")
+async def plan_pause(_user: Annotated[str, Depends(require_user)]) -> dict:
+    return await get_engine().pause()
+
+
+@router.post("/emergency-close")
+async def plan_emergency(_user: Annotated[str, Depends(require_user)]) -> dict:
+    return await get_engine().emergency_close()