B21: HUD #159

Summary

Implement the in-game heads-up display showing ship status, weapons, shields, targeting, and score.

Elements

• Ship hull HP bar
• Shield status (6 facings with health indicators)
• Weapon readiness indicators (phaser charge, torpedo reload)
• Subsystem status panel
• Target info (name, distance, hull %, shield status)
• Minimap / radar (nearby ships and objects)
• Score display
• Chat message overlay
• Damage direction indicator

Acceptance Criteria

• All HUD elements render and update in real time
• Shield facings display correct health
• Weapon indicators show charge/reload state
• Target info updates as player targets different ships

Depends on: #157 (LCARS UI), #150 (combat wiring)
Blocks: #120