fix(members): link sponsors to bills and fix member search

- Poller now fetches bill detail on insert to get sponsor (list endpoint
  has no sponsor data)
- Add backfill_sponsor_ids task + admin endpoint + UI button to fix the
  1,616 existing bills with NULL sponsor_id
- Member name search now matches both "Last, First" and "First Last"
  using split_part() on the stored name column; same fix applied to
  global search
- Load Bill.sponsor relationship eagerly in get_member_bills to prevent
  MissingGreenlet error during Pydantic serialization
- Remove .trim() on search onChange so spaces can be typed

Authored-By: Jack Levy

backend/app/api/search.py

@@ -1,5 +1,5 @@
 from fastapi import APIRouter, Depends, Query
-from sqlalchemy import select, text
+from sqlalchemy import func, or_, select, text
 from sqlalchemy.ext.asyncio import AsyncSession
 
 from app.database import get_db
@@ -38,10 +38,17 @@ async def search(
             seen.add(b.bill_id)
             bills.append(b)
 
-    # Fuzzy member search
+    # Fuzzy member search — matches "Last, First" and "First Last"
+    first_last = func.concat(
+        func.split_part(Member.name, ", ", 2), " ",
+        func.split_part(Member.name, ", ", 1),
+    )
     member_results = await db.execute(
         select(Member)
-        .where(Member.name.ilike(f"%{q}%"))
+        .where(or_(
+            Member.name.ilike(f"%{q}%"),
+            first_last.ilike(f"%{q}%"),
+        ))
         .order_by(Member.last_name)
         .limit(10)
     )