[micycle1]

Summary

• Better menus + UI sound effects: reworked the main, pause, settings, multiplayer and confirmation menus around shared MenuStyle / MenuNav helpers. Adds a new Dropdown widget, improves Slider and Button, adds hover/click sounds (ui_hover.wav, ui_click.wav) and a new intro BGM track.
• Time-based animation and physics: adds a Time class so movement, animation, particles, projectiles and the camera use delta time instead of being tied to frame rate. This covers the player, enemies, objects and the particle system.
• Better modify (editor) mode: adds a new TilePalette scene for choosing tiles, cleans up GameplayScene and the editor item handling, and improves the inventory and modify gameplay modes.
• Menu and game sound options + resolution settings: separate volume controls for menu and in-game audio, plus resolution options in graphics settings. Persisted through Options; menu logic moved out of MainMenu into SideScroller.
• Particles drawn on their own canvas: particles now render to a separate graphics layer.
• Standalone MenuBackground class: the animated menu background is now its own reusable component.