Port to MC 26.2

[Weyne1]

Port to 26.2

Changes:

• Updated mod to Minecraft version 26.2
• Added alpha animation support for PIP elements
• Added background animation support for text widgets
• Implemented constant alpha interpolation (EASE_OUT_CUBIC) for all animations to prevent flickering with certain non-linear curves
• Bumped mod version to 0.5.0

Fixes:

• Fixed inability to disable custom animation for a specific container in the UI config
• Fixed animation for complex curves (such as EASE_OUT_ELASTIC) where the element would not render at all when the scale was negative

Refactoring:

• Reorganized mixin packages
• Removed unnecessary hover handling for widgets during animation
• Removed redundant accessors in favor of new vanilla public getters

Closes #2