fix: add vertical_id and vertical slug filter params to shows endpoint

backend/routers/shows.py

@@ -40,6 +40,8 @@ def read_shows(
     venue_id: int = None,
     tour_id: int = None,
     year: int = None,
+    vertical: str = None,  # Single vertical slug filter
+    vertical_id: int = None,  # Vertical ID filter
     vertical_slugs: List[str] = Query(None),
     status: str = Query(default=None, regex="^(past|upcoming)$"),
     tiers: List[str] = Query(None),
@@ -73,6 +75,12 @@ def read_shows(
     
     if vertical_slugs:
         query = query.join(Vertical).where(Vertical.slug.in_(vertical_slugs))
+    elif vertical:
+        # Single vertical slug filter
+        query = query.join(Vertical).where(Vertical.slug == vertical)
+    
+    if vertical_id:
+        query = query.where(Show.vertical_id == vertical_id)
         
     if status:
         from datetime import datetime