Fixed tutorial and multiplayer connection flow issues: — Landmark Battle Steam update #162964

Fixed tutorial and multiplayer connection flow issues: - Reduced first-time stutter in the tutorial when passing buildings by prewarming building transparency materials. - Improved the multiplayer flow after both players accept a match, addressing cases where the game could remain stuck on the loading screen. - Increased card selection scene loading priority and added loading timeout protection with diagnostic logs. - Fixed blank error dialogs when returning to the lobby after multiplayer loading failures. A readable error message is now shown.