Add Rate Monitor app — Booking.com + direct booking engine competitor rates

Combines Booking.com Playwright scraper (from forecasting), direct booking
engine scraper (ported from laptop-archive/guestline-monitor), and Newbook
own-hotel rates into one focused tool. Four views: Bookability, Market View
(with price index badges + direct rate sub-rows), Direct Rates (per-competitor
room breakdown, min-stay flags, hotel config/discovery), Rate Analysis
(advance purchase curve, DOW chart, rate timeline, comparison table).

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/auth.py

@@ -0,0 +1,69 @@
+"""
+Auth middleware — verifies the stack's hnf_session cookie using the shared
+CENTRAL_AUTH_SECRET.
+"""
+import os
+from typing import Optional
+
+from fastapi import Depends, HTTPException, Request, status
+from jose import JWTError, jwt
+
+CENTRAL_AUTH_SECRET = os.getenv("CENTRAL_AUTH_SECRET", "")
+JWT_ALGORITHM = "HS256"
+APP_SLUG = os.getenv("APP_SLUG", "rates")
+
+
+async def get_current_user(request: Request) -> dict:
+    token = request.cookies.get("hnf_session")
+    if not token:
+        raise HTTPException(status_code=status.HTTP_401_UNAUTHORIZED, detail="Not authenticated")
+
+    try:
+        payload = jwt.decode(token, CENTRAL_AUTH_SECRET, algorithms=[JWT_ALGORITHM])
+    except JWTError:
+        raise HTTPException(status_code=status.HTTP_401_UNAUTHORIZED, detail="Invalid session")
+
+    apps = payload.get("apps", [])
+    if APP_SLUG not in apps:
+        raise HTTPException(status_code=status.HTTP_403_FORBIDDEN, detail="No permission for this app")
+
+    prefix = f"{APP_SLUG}:"
+    raw_caps = payload.get("caps", [])
+    if isinstance(raw_caps, list):
+        caps = [c[len(prefix):] for c in raw_caps if c.startswith(prefix)]
+    else:
+        caps = []
+
+    is_admin = payload.get("is_admin", False)
+
+    return {
+        "id": 0,
+        "username": payload.get("sub", ""),
+        "email": payload.get("sub", ""),
+        "display_name": payload.get("name", ""),
+        "name": payload.get("name", ""),
+        "is_admin": is_admin,
+        "caps": caps,
+        "role": "admin" if is_admin else "user",
+    }
+
+
+def has_cap(user: dict, cap: str) -> bool:
+    return user.get("is_admin", False) or cap in user.get("caps", [])
+
+
+def require_cap(cap: str):
+    async def checker(user: dict = Depends(get_current_user)):
+        if not has_cap(user, cap):
+            raise HTTPException(
+                status_code=status.HTTP_403_FORBIDDEN,
+                detail=f"Missing capability: {cap}",
+            )
+        return user
+    return checker
+
+
+async def get_admin_user(user: dict = Depends(get_current_user)) -> dict:
+    if not user.get("is_admin", False):
+        raise HTTPException(status_code=status.HTTP_403_FORBIDDEN, detail="Admin access required")
+    return user