Reorganize code to minimize bank switching

Performance optimization: Reorganize code structure to minimize bank switching overhead.

Current issues:
- Related functions scattered across different banks
- Frequent gosub calls that cross bank boundaries
- Subroutines called from multiple banks

Goals:
1. Group related functionality in the same bank
2. Minimize cross-bank subroutine calls
3. Keep frequently called functions in easily accessible banks
4. Reduce bank switching overhead during gameplay

Process:
1. Analyze current bank usage and cross-bank calls
2. Identify frequently called subroutines
3. Group related functions by functionality
4. Reorganize bank assignments to minimize switching
5. Update gosub calls to stay within same bank when possible

Bank organization suggestions:
- Bank 1: Core game loop and main routines
- Bank 2: Player input and movement
- Bank 3: Combat and collision detection
- Bank 4: Rendering and display
- Bank 5: Sound and music
- Bank 6: Menu systems and character select

Priority: Performance optimization after core build issues are resolved.
Note: This requires careful analysis of call patterns and may require significant restructuring.