Constant MAX_DECOMPRESSED_BYTES 

pub const MAX_DECOMPRESSED_BYTES: usize = _; // 16_777_216usize

Hard cap on the decompressed size of a single offloaded blob. Same 16 MiB ceiling the transcripts module enforces — defends against pathological zstd bombs landing through deref. v0.8.0 may raise this for the Mermaid-canvas use case after threat-modelling.