feat(stock-webai): /api/webai/portfolio + pnl_pct augment

Reuses get_portfolio() and adds pnl_pct (ratio, profit_rate/100) to
each holding plus total_pnl_pct to summary. 4 integration tests pass.
verify_webai_key dependency enforced.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

stock/app/main.py

@@ -24,6 +24,7 @@ from .db import (
 from .scraper import fetch_market_news, fetch_major_indices
 from .price_fetcher import get_current_prices, get_current_prices_detail
 from .ai_summarizer import summarize_news, OllamaError
+from .auth import verify_webai_key
 
 app = FastAPI()
 
@@ -384,6 +385,26 @@ def get_portfolio():
     }
 
 
+def _augment_portfolio_with_pnl_pct(raw: dict) -> dict:
+    """Add pnl_pct (ratio) to each holding and total_pnl_pct to summary."""
+    holdings = []
+    for h in raw["holdings"]:
+        pnl_pct = round(h["profit_rate"] / 100, 6) if h.get("profit_rate") is not None else None
+        holdings.append({**h, "pnl_pct": pnl_pct})
+
+    summary = dict(raw["summary"])
+    rate = summary.get("total_profit_rate")
+    summary["total_pnl_pct"] = round(rate / 100, 6) if rate is not None else 0.0
+
+    return {"holdings": holdings, "cash": raw["cash"], "summary": summary}
+
+
+@app.get("/api/webai/portfolio", dependencies=[Depends(verify_webai_key)])
+def get_webai_portfolio():
+    """web-ai 전용 portfolio (인증 필수, pnl_pct 비율 필드 추가)."""
+    return _augment_portfolio_with_pnl_pct(get_portfolio())
+
+
 @app.post("/api/portfolio", status_code=201)
 def create_portfolio_item(req: PortfolioItemRequest):
     """포트폴리오 종목 추가"""