Add filter controls to admin tables

Pokemon (type), Evolutions (trigger), Games (region/generation),
and Runs (status/game) now have dropdown filters alongside search.
Server-side filtering for paginated tables, client-side for small datasets.

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

backend/src/app/api/evolutions.py

@@ -21,6 +21,7 @@ router = APIRouter()
 @router.get("/evolutions", response_model=PaginatedEvolutionResponse)
 async def list_evolutions(
     search: str | None = Query(None),
+    trigger: str | None = Query(None),
     limit: int = Query(50, ge=1, le=500),
     offset: int = Query(0, ge=0),
     session: AsyncSession = Depends(get_session),
@@ -44,6 +45,8 @@ async def list_evolutions(
                 func.lower(Evolution.item).contains(search_lower),
             )
         )
+    if trigger:
+        base_query = base_query.where(Evolution.trigger == trigger)
 
     # Count total (without eager loads)
     count_base = select(Evolution)
@@ -60,6 +63,8 @@ async def list_evolutions(
                 func.lower(Evolution.item).contains(search_lower),
             )
         )
+    if trigger:
+        count_base = count_base.where(Evolution.trigger == trigger)
     count_query = select(func.count()).select_from(count_base.subquery())
     total = (await session.execute(count_query)).scalar() or 0