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/api/bosses.ts

@@ -1,7 +1,14 @@
 import { api } from './client'
-import type { BossBattle, BossResult, CreateBossResultInput } from '../types/game'
+import type {
+  BossBattle,
+  BossResult,
+  CreateBossResultInput,
+} from '../types/game'
 
-export function getGameBosses(gameId: number, all?: boolean): Promise<BossBattle[]> {
+export function getGameBosses(
+  gameId: number,
+  all?: boolean
+): Promise<BossBattle[]> {
   const params = all ? '?all=true' : ''
   return api.get(`/games/${gameId}/bosses${params}`)
 }
@@ -10,10 +17,16 @@ export function getBossResults(runId: number): Promise<BossResult[]> {
   return api.get(`/runs/${runId}/boss-results`)
 }
 
-export function createBossResult(runId: number, data: CreateBossResultInput): Promise<BossResult> {
+export function createBossResult(
+  runId: number,
+  data: CreateBossResultInput
+): Promise<BossResult> {
   return api.post(`/runs/${runId}/boss-results`, data)
 }
 
-export function deleteBossResult(runId: number, resultId: number): Promise<void> {
+export function deleteBossResult(
+  runId: number,
+  resultId: number
+): Promise<void> {
   return api.del(`/runs/${runId}/boss-results/${resultId}`)
 }