Admit BMP metadata and pixels using the existing bounded image decoder.
Preserve row orientation and padding, palette pixels, and malformed-input
rejection; support image loads and Canvas/ImageBitmap pixel consumers.
Validation: fmt, workspace all-target/all-feature clippy with -D warnings;
22595 native tests pass at 32 threads with zero retries; nine BMP pixel
contracts match Chromium; image/network regression cohorts retained.
ldm0
wslee