feat: complete engine and editor subsystems (Stages 1-5 from TODO_ARTEM)
- Stage 1: Eliminate fish-eye distortion with precomputed tangential ray offset table and fractional DDA depth
- Stage 2: Full asset management in EblanStudio (stb_image/stb_image_write, 128x128 BGRA texture packaging, WAV sound manager)
- Stage 3: Multi-level room streaming, LevelTransition/CELL_PORTAL trigger system, 16-frame screen fade to black
- Stage 4: 60Hz cutscene engine in pure x86 ASM (v4 binary track, waypoint camera motion, shortest-arc pan, CP1251 Russian subtitles, letterbox overlay, audio)
- Stage 5: EblanStudio cutscene timeline (F6) and windowless Live ASM Viewport over shared-memory IPC directly rendered into DX11
- Tooling & Tests: comprehensive regression test suite (94 editor + 107 engine tests), IPC tests, and cutscene demo
Artvasil09
a1d1baa869