fix(gpu): Use GetTextureAsset() for procedural texture loading

Fixed demo64k crash caused by incorrect manual parsing of procedural
texture headers in effects code.

Problem:
- Procedural textures (NOISE_TEX) have 8-byte header (width, height)
- Effects checked size == 256*256*4 (262,144 bytes)
- Actual size was 262,152 bytes (including header)
- Size mismatch caused texture load failure → WebGPU bind group panic

Solution:
- Use GetTextureAsset() helper that properly parses header
- Returns TextureAsset{width, height, pixels} with pixels pointing after header
- Updated flash_cube_effect.cc and hybrid_3d_effect.cc

Result:
- Demo runs without crashes
- NOISE_TEX loads correctly (256x256 RGBA8)
- No more WebGPU bind group errors

0 files changed, 0 insertions, 0 deletions