Terminal Block Protocol (TBP) v1: wire types and codec.
TBP is an OSC escape sequence carrying a MIME bundle, directly inspired by
Jupyter's display_data message. A tool emits a block as one escape; the
terminal selects the richest MIME representation it can render and falls back
toward text/plain. Terminals that do not understand TBP ignore the escape.
The wire form is documented normatively in
docs/terminal-block-protocol-spec.md; this crate is its reference codec.
See [encode] and [decode] for the byte-stream entry points.