Demo Content Update

Main changes in the new demo version:Adjusted some CG and performancesOptimized the chapter selection UI and added switch & confirm buttonsEnlarged the dialogue boxFixed character position bug during fast-forwardFixed desktop pet animation switching bugUnlocked more desktop pet animations in the demoFixed the bug where the desktop pet does not stay on top when clicking the taskbar iconOptimized the computer simulation interface and added auto-play functionFixed Pomodoro timer font color bug