Add pre-commit hooks for linting and formatting

Set up pre-commit framework with ruff (backend) and ESLint/Prettier/tsc
(frontend) hooks to catch issues locally before CI. Auto-format all
frontend files with Prettier to comply with the new check.

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

frontend/src/components/HofTeamModal.tsx

@@ -8,7 +8,12 @@ interface HofTeamModalProps {
   isPending: boolean
 }
 
-export function HofTeamModal({ alive, onSubmit, onSkip, isPending }: HofTeamModalProps) {
+export function HofTeamModal({
+  alive,
+  onSubmit,
+  onSkip,
+  isPending,
+}: HofTeamModalProps) {
   const [selected, setSelected] = useState<Set<number>>(() => {
     // Pre-select all if 6 or fewer
     if (alive.length <= 6) return new Set(alive.map((e) => e.id))