9P2000.L wire protocol with owned and allocation-free codecs.
Shared by the ZeroFS 9P server and the ninep-client crate so both sides
speak the exact same messages. Includes the ZeroFS-private Trebind/Rrebind
reconnect extension.
All supported messages use [slice_codec]. It encodes into caller-owned
buffers and decodes borrowed views without allocating. The owned API uses
Bytes storage, so decoded strings and payloads share the received frame.
With default features disabled, the codec requires only core. The owned
feature adds the userspace API in no_std + alloc environments.