The cover multipart path called Field::bytes(), buffering the entire field
into memory before parse_image checked max_file_bytes — an oversized cover
was fully allocated before rejection. Add read_capped/push_capped, which
reject with 413 as soon as the running total exceeds the cap (the offending
chunk is never copied in), and route both cover handlers and stage_image_part
through it.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>