add paper trading: mark a setup as taken, track open P&L, sell

New paper_trades table (migration 007) + service/router. "Mark as taken" on each
setup card (shares prefilled from position sizing, entry from current price, both
editable) records a simulated trade. Overview gains an Open Trades table that
marks each position to the latest close — P&L in $, %, and R-multiples — with a
total unrealized P&L footer and a Sell button to close at the current price.
Closed trades are retained for future realized-P&L reporting.

Deploy: alembic upgrade (new paper_trades table).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

app/routers/paper_trades.py

@@ -0,0 +1,69 @@
+"""Paper trades router — take, list, and close simulated trades."""
+
+from fastapi import APIRouter, Depends, Query
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from app.dependencies import get_db, require_access
+from app.models.user import User
+from app.schemas.common import APIEnvelope
+from app.schemas.paper_trade import PaperTradeClose, PaperTradeCreate, PaperTradeResponse
+from app.services import paper_trade_service
+
+router = APIRouter(tags=["paper-trades"])
+
+
+def _resp(trade, symbol: str, current_price=None) -> dict:
+    return PaperTradeResponse(
+        id=trade.id,
+        symbol=symbol,
+        direction=trade.direction,
+        entry_price=trade.entry_price,
+        shares=trade.shares,
+        stop_loss=trade.stop_loss,
+        target=trade.target,
+        status=trade.status,
+        opened_at=trade.opened_at,
+        close_price=trade.close_price,
+        closed_at=trade.closed_at,
+        current_price=current_price,
+    ).model_dump(mode="json")
+
+
+@router.get("/paper-trades", response_model=APIEnvelope)
+async def list_paper_trades(
+    status: str | None = Query(default=None, pattern=r"^(open|closed)$"),
+    user: User = Depends(require_access),
+    db: AsyncSession = Depends(get_db),
+) -> APIEnvelope:
+    rows = await paper_trade_service.list_trades(db, user.id, status=status)
+    data = [PaperTradeResponse(**r).model_dump(mode="json") for r in rows]
+    return APIEnvelope(status="success", data=data)
+
+
+@router.post("/paper-trades", response_model=APIEnvelope, status_code=201)
+async def create_paper_trade(
+    body: PaperTradeCreate,
+    user: User = Depends(require_access),
+    db: AsyncSession = Depends(get_db),
+) -> APIEnvelope:
+    trade = await paper_trade_service.create_trade(
+        db, user.id,
+        symbol=body.symbol,
+        direction=body.direction,
+        entry_price=body.entry_price,
+        shares=body.shares,
+        stop_loss=body.stop_loss,
+        target=body.target,
+    )
+    return APIEnvelope(status="success", data=_resp(trade, body.symbol.strip().upper()))
+
+
+@router.post("/paper-trades/{trade_id}/close", response_model=APIEnvelope)
+async def close_paper_trade(
+    trade_id: int,
+    body: PaperTradeClose,
+    user: User = Depends(require_access),
+    db: AsyncSession = Depends(get_db),
+) -> APIEnvelope:
+    trade = await paper_trade_service.close_trade(db, user.id, trade_id, body.close_price)
+    return APIEnvelope(status="success", data={"id": trade.id, "status": trade.status})