B10: Ship movement + input #148

Summary

Implement player ship movement controlled by keyboard and mouse input. The player can fly their ship around the scene.

Requirements

• SDL3 keyboard and mouse input handling
• Ship movement: forward/reverse thrust, yaw, pitch
• Mouse look for targeting
• Keybinding system (configurable)
• Camera follows player ship (chase cam)
• Movement physics: momentum, turn rate limits (from ship data)

Acceptance Criteria

• Player can fly ship with keyboard/mouse
• Movement feels responsive but not twitchy
• Camera tracks player ship smoothly
• Multiple input methods work (keyboard, mouse)

Depends on: #144 (ship rendering), #145 (skybox/lighting)
Blocks: #120