Improved billing compliance and app polish.

- Updated Google Play Billing to version 8.3.0
- Added theme options in Settings
- Refined premium and home screen layout
- General fixes and stability improvements

A calmer, clearer experience — designed for consistency.

• Brand new visual redesign with softer colors and improved clarity
• Cleaner habit cards and progress tracking
• Improved onboarding for easier goal setup
• Better balance between motivation and flexibility
• Subtle UI refinements for smoother daily use

This update focuses on helping you come back — even after missed days.