ipc.rs tests (4 tests):
- request_msgpack_roundtrip: LaunchApp serializes and deserializes with
correct field values.
- response_msgpack_roundtrip: LaunchAck round-trips through MessagePack.
- frame_write_read_roundtrip: write_frame encodes a 4-byte LE length
header + body; read_frame decodes the framed request correctly.
- read_frame_eof_returns_none: empty stream returns None without error.
main.rs tests (5 tests):
- registry_launch_increments_id: each launch returns a strictly
increasing session ID.
- registry_terminate_known_session: terminate returns true and state
transitions to NotFound.
- registry_terminate_unknown_returns_false: terminate on missing ID
returns false.
- registry_running_ids_reflects_live_sessions: running_ids returns all
active sessions; terminated sessions are removed.
- registry_state_not_found_for_unknown: querying an unknown session ID
returns AppStateKind::NotFound.
Also extends scripts/wsl-test.sh to run weft-appd tests alongside
weft-compositor tests.