Implements parse_bmp (24/32-bit uncompressed BMP to RGBA), GpuTexture with wgpu 28.0 write_texture API (TexelCopyTextureInfo/TexelCopyBufferLayout), bind_group_layout, white_1x1 fallback, and 3 BMP parser unit tests. Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>