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/(main)/shop/[id]/page.tsx

@@ -25,8 +25,8 @@ export default async function ShopPage({ params }: PageProps) {
   }
 
   const [shopPlayers, allServices] = await Promise.all([listPlayersByShop(shop.id), listServices()])
-  const playerIds = shopPlayers.map((p) => p.id)
-  const shopServices = allServices.filter((s) => playerIds.includes(s.playerId))
+  const playerIds = new Set(shopPlayers.map((player) => String(player.id)))
+  const shopServices = allServices.filter((service) => playerIds.has(String(service.playerId)))
   const shopReviews = await listReviews()
   const sortedSections = getShopSections(shop).filter((s) => s.enabled)