Add IMGUI HUD overlay showing HP, wave, score, and enemy count.
Display centered Game Over panel with final score and restart prompt.
Add procedural sine-wave audio clips for shooting (440Hz) and enemy
kills (220Hz) via voltex_audio. Player blinks white during invincibility.
Press R to restart after game over.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Static arena with 20x20 floor and 4 box obstacles rendered using the
forward PBR pipeline with shadow mapping. Fixed quarter-view camera
at (0, 15, 10) looking at origin.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
