Add genlocke cumulative graveyard with backend endpoint and UI

Aggregates all fainted encounters across every leg of a genlocke into a
unified graveyard view. Backend serves GET /genlockes/{id}/graveyard with
per-entry leg/game context and summary stats (total deaths, deaths per
leg, deadliest leg). Frontend adds a toggle button on the genlocke detail
page that reveals a filterable/sortable grid of grayscale Pokemon cards.

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

frontend/src/pages/GenlockeDetail.tsx

@@ -1,9 +1,9 @@
 import { Link, useParams } from 'react-router-dom'
 import { useGenlocke } from '../hooks/useGenlockes'
 import { usePokemonFamilies } from '../hooks/usePokemon'
-import { StatCard, RuleBadges } from '../components'
+import { GenlockeGraveyard, StatCard, RuleBadges } from '../components'
 import type { GenlockeLegDetail, RetiredPokemon, RunStatus } from '../types'
-import { useMemo } from 'react'
+import { useMemo, useState } from 'react'
 
 const statusColors: Record<RunStatus, string> = {
   completed: 'bg-blue-500',
@@ -86,6 +86,8 @@ export function GenlockeDetail() {
   const { data: genlocke, isLoading, error } = useGenlocke(id)
   const { data: familiesData } = usePokemonFamilies()
 
+  const [showGraveyard, setShowGraveyard] = useState(false)
+
   const activeLeg = useMemo(() => {
     if (!genlocke) return null
     return genlocke.legs.find((l) => l.runStatus === 'active') ?? null
@@ -285,9 +287,12 @@ export function GenlockeDetail() {
             </Link>
           )}
           <button
-            disabled
-            className="px-4 py-2 bg-gray-200 dark:bg-gray-700 text-gray-500 dark:text-gray-400 rounded-lg font-medium cursor-not-allowed"
-            title="Coming soon"
+            onClick={() => setShowGraveyard((v) => !v)}
+            className={`px-4 py-2 rounded-lg font-medium transition-colors ${
+              showGraveyard
+                ? 'bg-red-600 text-white hover:bg-red-700'
+                : 'bg-gray-200 dark:bg-gray-700 text-gray-700 dark:text-gray-300 hover:bg-gray-300 dark:hover:bg-gray-600'
+            }`}
           >
             Graveyard
           </button>
@@ -300,6 +305,16 @@ export function GenlockeDetail() {
           </button>
         </div>
       </section>
+
+      {/* Graveyard */}
+      {showGraveyard && (
+        <section>
+          <h2 className="text-lg font-semibold text-gray-900 dark:text-gray-100 mb-4">
+            Cumulative Graveyard
+          </h2>
+          <GenlockeGraveyard genlockeId={id} />
+        </section>
+      )}
     </div>
   )
 }