Fix news risk window query parsing

backend/src/alphapulse/api/risk.py

@@ -1,6 +1,7 @@
 """Authenticated news risk research endpoints."""
 from datetime import UTC, datetime, timedelta
-from typing import Annotated, Literal
+from enum import IntEnum
+from typing import Annotated
 from fastapi import APIRouter, Depends, HTTPException, Query
 from pydantic import BaseModel, Field
 from sqlalchemy import select, func
@@ -17,6 +18,12 @@ router = APIRouter(prefix='/api/risk', tags=['risk'], dependencies=[Depends(requ
 DB = Annotated[AsyncSession, Depends(get_session)]
 
 
+class RiskWindow(IntEnum):
+    DAY = 24
+    TWO_DAYS = 48
+    WEEK = 168
+
+
 class SettingsIn(BaseModel):
     enabled: bool = False
     provider_id: int = Field(gt=0)
@@ -72,7 +79,7 @@ async def coverage(session):
 
 
 @router.get('/overview')
-async def overview(session: DB, hours: Literal[24, 48, 168] = 24):
+async def overview(session: DB, hours: RiskWindow = RiskWindow.DAY):
     now = datetime.now(UTC); cutoff = now - timedelta(hours=hours)
     counts = dict((await session.execute(select(RiskEvent.stars, func.count()).where(
         RiskEvent.updated_at >= cutoff, RiskEvent.result["verification"].astext != "insufficient").group_by(RiskEvent.stars))).all())
@@ -86,7 +93,7 @@ async def overview(session: DB, hours: Literal[24, 48, 168] = 24):
 
 
 @router.get('/events')
-async def events(session: DB, hours: Literal[24, 48, 168] | None = None, stars: int = Query(1, ge=0, le=5),
+async def events(session: DB, hours: RiskWindow | None = None, stars: int = Query(1, ge=0, le=5),
                  q: str = '', start: datetime | None = None, end: datetime | None = None,
                  page: int = Query(1, ge=1), limit: int = Query(20, ge=1, le=100)):
     conditions = [RiskEvent.stars >= stars]