Wire-compatible with the Python client's _ft protocol (offer/accept/reject/
chunk/done, 64KB chunks, SHA-256 verified), over the encrypted channel:
- ft.rs: read_payload (file or tar'd directory), save/extract with a zip-slip
guard (relative-only, no .. / absolute; unpack_in double-checks), SHA-256.
- /send <file> and /sendd <dir>; receiver sees an offer banner, /accept or
/reject; chunks stream in the background and the result is verified + saved
to ./downloads (directories extracted in place).
- Refactor: all outgoing ws frames now funnel through an mpsc channel drained
(batched) by the run loop, so the background chunk-sender and the PTY relay
transmit without owning the socket.
- ui.rs: pending-offer banner on the input bar.
Tests: 7 cargo tests (file + dir tar round-trip, traversal guard, + crypto/sbx).
Verified live: two TUIs, file and directory transfer, SHA-256 verified, saved.
Note: dropping accepted files into the active sandbox VM dir is a future add-on.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
