feat: complete Voltex Engine + Survivor game

11 crates, 13 examples (including survivor_game), 255 tests
Phase 1-8 fully implemented + playable survival game demo

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Cargo.lock

@@ -1885,6 +1885,8 @@ dependencies = [
  "env_logger",
  "log",
  "pollster",
+ "voltex_audio",
+ "voltex_editor",
  "voltex_math",
  "voltex_platform",
  "voltex_renderer",