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/admin/RouteEncounterFormModal.tsx

@@ -1,12 +1,22 @@
 import { type FormEvent, useState } from 'react'
 import { FormModal } from './FormModal'
 import { PokemonSelector } from './PokemonSelector'
-import { METHOD_ORDER, METHOD_CONFIG, getMethodLabel } from '../EncounterMethodBadge'
-import type { RouteEncounterDetail, CreateRouteEncounterInput, UpdateRouteEncounterInput } from '../../types'
+import {
+  METHOD_ORDER,
+  METHOD_CONFIG,
+  getMethodLabel,
+} from '../EncounterMethodBadge'
+import type {
+  RouteEncounterDetail,
+  CreateRouteEncounterInput,
+  UpdateRouteEncounterInput,
+} from '../../types'
 
 interface RouteEncounterFormModalProps {
   encounter?: RouteEncounterDetail
-  onSubmit: (data: CreateRouteEncounterInput | UpdateRouteEncounterInput) => void
+  onSubmit: (
+    data: CreateRouteEncounterInput | UpdateRouteEncounterInput
+  ) => void
   onClose: () => void
   isSubmitting?: boolean
   onDelete?: () => void
@@ -25,11 +35,18 @@ export function RouteEncounterFormModal({
 
   const initialMethod = encounter?.encounterMethod ?? ''
   const isKnownMethod = METHOD_ORDER.includes(initialMethod)
-  const [selectedMethod, setSelectedMethod] = useState(isKnownMethod ? initialMethod : initialMethod ? 'other' : '')
-  const [customMethod, setCustomMethod] = useState(isKnownMethod ? '' : initialMethod)
-  const encounterMethod = selectedMethod === 'other' ? customMethod : selectedMethod
+  const [selectedMethod, setSelectedMethod] = useState(
+    isKnownMethod ? initialMethod : initialMethod ? 'other' : ''
+  )
+  const [customMethod, setCustomMethod] = useState(
+    isKnownMethod ? '' : initialMethod
+  )
+  const encounterMethod =
+    selectedMethod === 'other' ? customMethod : selectedMethod
 
-  const [encounterRate, setEncounterRate] = useState(String(encounter?.encounterRate ?? ''))
+  const [encounterRate, setEncounterRate] = useState(
+    String(encounter?.encounterRate ?? '')
+  )
   const [minLevel, setMinLevel] = useState(String(encounter?.minLevel ?? ''))
   const [maxLevel, setMaxLevel] = useState(String(encounter?.maxLevel ?? ''))
 
@@ -70,7 +87,9 @@ export function RouteEncounterFormModal({
         />
       )}
       <div>
-        <label className="block text-sm font-medium mb-1">Encounter Method</label>
+        <label className="block text-sm font-medium mb-1">
+          Encounter Method
+        </label>
         <select
           required
           value={selectedMethod}
@@ -107,7 +126,9 @@ export function RouteEncounterFormModal({
         )}
       </div>
       <div>
-        <label className="block text-sm font-medium mb-1">Encounter Rate (%)</label>
+        <label className="block text-sm font-medium mb-1">
+          Encounter Rate (%)
+        </label>
         <input
           type="number"
           required