feat: add player ownership helper to player-manager API

Added getPlayerOwnershipMap() as a convenience re-export of the
centralized buildPlayerOwnershipMap() utility.

This allows modules to access player ownership data through the
player-manager API, which is the natural home for player-related
server-side operations.

New function:
- getPlayerOwnershipMap(roomId?) - Returns PlayerOwnershipMap

Benefits:
- Consistent API: player data + ownership through same module
- Discovery: developers naturally look in player-manager for player ops
- Flexibility: can add room-filtering logic in future if needed
- Documentation: JSDoc example shows usage pattern

Example usage:
  const ownership = await getPlayerOwnershipMap()
  const isOwned = ownership[playerId] === userId

This is phase 3 of the player ownership centralization plan.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

apps/web/src/lib/arcade/player-manager.ts

@@ -6,6 +6,7 @@
 import { and, eq } from 'drizzle-orm'
 import { db, schema } from '@/db'
 import type { Player } from '@/db/schema/players'
+import { type PlayerOwnershipMap, buildPlayerOwnershipMap } from './player-ownership'
 
 /**
  * Get all players for a user (regardless of isActive status)
@@ -128,3 +129,21 @@ export async function getPlayers(playerIds: string[]): Promise<Player[]> {
 
   return players
 }
+
+/**
+ * Get player ownership map for a room
+ *
+ * Convenience re-export of the centralized player ownership utility.
+ * This allows other modules to get player ownership data through
+ * the player-manager API.
+ *
+ * @param roomId - Optional room ID (currently unused by underlying utility)
+ * @returns Promise resolving to playerOwnership map (playerId -> userId)
+ *
+ * @example
+ * const ownership = await getPlayerOwnershipMap()
+ * const isOwned = ownership[playerId] === userId
+ */
+export async function getPlayerOwnershipMap(roomId?: string): Promise<PlayerOwnershipMap> {
+  return buildPlayerOwnershipMap(roomId)
+}