**Problem:**
- player-ownership.ts imported drizzle-orm and @/db at top level
- When RoomMemoryPairsProvider imported client-safe utilities, Webpack bundled ALL imports including database code
- This caused hydration error: "The 'original' argument must be of type Function"
- Node.js util.promisify was being called in browser context
**Solution:**
1. Created player-ownership.client.ts with ONLY client-safe utilities
- No database imports
- Safe to import from 'use client' components
- Contains: buildPlayerOwnershipFromRoomData(), buildPlayerMetadata(), helper functions
2. Updated player-ownership.ts to re-export client utilities and add server-only functions
- Re-exports everything from .client.ts
- Adds buildPlayerOwnershipMap() (async, database-backed)
- Safe to import from server components/API routes
3. Updated RoomMemoryPairsProvider to import from .client.ts
**Result:**
- No more hydration errors on /arcade/room
- Client bundle doesn't include database code
- Server code can still use both client and server utilities
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>