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.

lib/api/players.ts

@@ -37,5 +37,5 @@ export async function getPlayerById(playerId: string): Promise<Player | undefine
 
 export async function listPlayersByShop(shopId: string): Promise<Player[]> {
   const players = await listPlayers()
-  return players.filter((player) => player.shopId === shopId)
+  return players.filter((player) => String(player.shopId) === shopId)
 }