fix(arcade-rooms): navigate to invite link after room creation

Previously, when creating a new room, users were navigated to
/arcade-rooms/{roomId}, which is the direct room route.

Now users are navigated to /join/{code}, which is the invite link
format. This provides a better user experience as it follows the
same flow as joining via an invite link.

Changes:
- Changed router.push from /arcade-rooms/{id} to /join/{code}

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

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

apps/web/src/app/arcade-rooms/page.tsx

@@ -70,7 +70,7 @@ export default function RoomBrowserPage() {
       }
 
       const data = await response.json()
-      router.push(`/arcade-rooms/${data.room.id}`)
+      router.push(`/join/${data.room.code}`)
     } catch (err) {
       console.error('Failed to create room:', err)
       showError('Failed to create room', err instanceof Error ? err.message : undefined)