feat(tty): implement raw chunk codec (ChunkReader/ChunkWriter, RawError)
Port of the alknet-tty POC's raw.rs into crates/alknet-tty/src/wire.rs.
The Phase 2 'raw carriage' wire format (ADR-052):
[stream_type: u8][length: u32 be][payload bytes].
- STREAM_STDIN/STDOUT/STDERR/CONTROL constants (0-3)
- CHUNK_HEADER_LEN (5) and MAX_CHUNK_LEN (16 MiB)
- RawError: Io / ConnectionClosed / InvalidStreamType / ChunkTooLarge
- Chunk struct with stdin/stdout/stderr/control constructors
- ChunkReader::read_chunk validates stream_type and length, returns
ConnectionClosed on clean UnexpectedEof (header or payload)
- ChunkWriter::write_chunk/write_stdin/write_control_json write
header + payload + flush
- Round-trip tests for all four stream types, InvalidStreamType (4),
ChunkTooLarge (> MAX_CHUNK_LEN), ConnectionClosed on truncated
header and payload, via tokio::io::duplex
glm-5.2
17713a5c27