Implement CPU player logic for all 16 characters

**Issue:** CPU player needs logic for each of the 16 characters and should only trigger the same functions that joystick would do for a human player.

**Current Status:**
- CPU player logic likely exists in `Source/Routines/PlayerInput.bas` or related files
- Need to ensure CPU can control all 16 characters with appropriate AI behavior
- CPU should use the same input functions as human players (joystick simulation)

**Requirements:**
- CPU player logic for all 16 characters:
- Bernie, Curling sweeper, Dragonet, EXO Pilot, Fat Tony, Megax, Harpy, Knight Guy, Frooty, Nefertem, Ninjish Guy, Pork Chop, Radish Goblin, Robo Tito, Ursulo, Veg Dog
- CPU should simulate joystick input rather than directly manipulating game state
- Each character should have appropriate AI behavior patterns
- CPU difficulty levels (easy, medium, hard) for different skill levels

**Technical Notes:**
- CPU player should call the same input handling functions as human players
- Use `PlayerInput.bas` functions but with AI-generated input instead of joystick reading
- Character-specific AI should be based on character abilities and playstyle

**Priority:** High
**Milestone:** 1