feat(bench): add Resource Bench Board page

Shows resources with available capacity in a selected date window.
- Filter by date range (with DateRangePresets), min hours/day slider, and free-text search
- Cards show role, chapter, available h/day with color-coded capacity bar
- Links to individual resource profiles
- "Bench" nav entry added to Resources section in AppShell

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

apps/web/src/app/(app)/bench/page.tsx

@@ -0,0 +1,5 @@
+import { BenchBoardClient } from "~/components/bench/BenchBoardClient.js";
+
+export default function BenchPage() {
+  return <BenchBoardClient />;
+}