docs: add README and LICENSE to Rust client and mux crates

README.md

@@ -0,0 +1,37 @@
+# DongLoRa Rust Client
+
+Rust client library for talking to a DongLoRa device — either directly
+over USB or through the [mux daemon](../../mux/).
+
+## What's in Here
+
+- `src/protocol.rs` — wire protocol types (`RadioConfig`, `Command`, `Response`, `ErrorCode`)
+- `src/codec.rs` — COBS framing, frame accumulator
+- `src/discovery.rs` — USB VID:PID device discovery
+- `src/transport.rs` — serial and mux socket transports
+- `src/client.rs` — high-level `Client<T>` with send/recv
+- `src/connect.rs` — auto-detection (mux socket, TCP, direct USB)
+
+## Usage
+
+```rust
+use donglora_client::*;
+
+let mut client = connect_default()?;
+client.ping()?;
+client.set_config(RadioConfig::default())?;
+client.start_rx()?;
+
+loop {
+    if let Some(Response::RxPacket { rssi, snr, payload }) = client.recv()? {
+        println!("RX rssi={rssi} snr={snr} len={}", payload.len());
+    }
+}
+```
+
+## Dependencies
+
+- `cobs` — COBS framing
+- `serialport` — USB serial communication
+- `anyhow` — error handling
+- `tracing` — logging