refactor: remove hardcoded display values and unused lib/id.ts

Delete hardcoded marketing stats in auth layout and ¥12,800
placeholder in owner dashboard. Remove lib/id.ts which is no
longer referenced by any module.

app/(dashboard)/dashboard/page.tsx

@@ -92,7 +92,9 @@ export default function DashboardPage() {
   const rating = isOwner ? (shop?.rating ?? 0) : (player?.rating ?? 0)
   const playerCount = shop?.playerCount ?? 0
   const completionRate = player?.completionRate ?? 0
-  const serviceCount = player ? services.filter((s) => s.playerId === player.id).length : 0
+  const serviceCount = player
+    ? services.filter((service) => String(service.playerId) === String(player.id)).length
+    : 0
 
   return (
     <div className="container mx-auto max-w-6xl px-4 py-8 space-y-8">
@@ -147,7 +149,7 @@ export default function DashboardPage() {
             )}
           </CardHeader>
           <CardContent>
-            <div className="text-2xl font-bold">{isOwner ? "¥12,800" : serviceCount}</div>
+            <div className="text-2xl font-bold">{isOwner ? "——" : serviceCount}</div>
           </CardContent>
         </Card>
       </div>