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

frontend/app/bills/page.tsx

@@ -45,7 +45,7 @@ export default function BillsPage() {
             type="text"
             placeholder="Search bills..."
             value={q}
-            onChange={(e) => { setQ(e.target.value.trim()); setPage(1); }}
+            onChange={(e) => { setQ(e.target.value); setPage(1); }}
             className="w-full pl-9 pr-3 py-2 text-sm bg-card border border-border rounded-md focus:outline-none focus:ring-1 focus:ring-primary"
           />
         </div>

frontend/app/members/page.tsx

@@ -32,7 +32,7 @@ export default function MembersPage() {
             type="text"
             placeholder="Search by name..."
             value={q}
-            onChange={(e) => { setQ(e.target.value.trim()); setPage(1); }}
+            onChange={(e) => { setQ(e.target.value); setPage(1); }}
             className="w-full pl-9 pr-3 py-2 text-sm bg-card border border-border rounded-md focus:outline-none"
           />
         </div>

frontend/app/settings/page.tsx

@@ -346,6 +346,12 @@ export default function SettingsPage() {
           >
             <RefreshCw className="w-3.5 h-3.5" /> Calculate Trends
           </button>
+          <button
+            onClick={() => trigger("sponsors", adminAPI.backfillSponsors)}
+            className="flex items-center gap-2 px-4 py-2 text-sm bg-muted hover:bg-accent rounded-md transition-colors"
+          >
+            <RefreshCw className="w-3.5 h-3.5" /> Backfill Sponsors
+          </button>
         </div>
         {Object.entries(taskIds).map(([name, id]) => (
           <p key={name} className="text-xs text-muted-foreground">{name}: task {id} queued</p>