Add chamber color badges, action history fallback, and task status polling

- Add chamberBadgeColor util: amber/gold for Senate, slate/silver for House
- Apply chamber badge to BillCard and bill detail header
- ActionTimeline: show latest_action_date/text as fallback when full history
  not yet fetched, with note that full history loads in background
- Manual Controls: poll task status every 5s after triggering, show spinning
  indicator while running, task ID prefix, and completion/failure state

Authored-By: Jack Levy

frontend/lib/utils.ts

@@ -44,6 +44,21 @@ export function partyBadgeColor(party?: string): string {
   return "bg-slate-500 text-white";
 }
 
+export function congressLabel(congress: number): string {
+  const lastTwo = congress % 100;
+  if (lastTwo >= 11 && lastTwo <= 13) return `${congress}th Congress`;
+  const suffixes: Record<number, string> = { 1: "st", 2: "nd", 3: "rd" };
+  return `${congress}${suffixes[congress % 10] ?? "th"} Congress`;
+}
+
+export function chamberBadgeColor(chamber?: string): string {
+  if (!chamber) return "bg-muted text-muted-foreground";
+  const c = chamber.toLowerCase();
+  if (c === "senate") return "bg-amber-100 text-amber-700 dark:bg-amber-900/30 dark:text-amber-400";
+  if (c.startsWith("house")) return "bg-slate-100 text-slate-600 dark:bg-slate-700/50 dark:text-slate-300";
+  return "bg-muted text-muted-foreground";
+}
+
 export function trendColor(score?: number): string {
   if (!score) return "text-muted-foreground";
   if (score >= 70) return "text-red-500";