Implement native UDP transport reliability (#52)

README.md

@@ -262,3 +262,13 @@ token and are shut down idempotently in network, manager, HTTP, then rate-limite
 order. Injected clocks support deterministic tests, while `Debug` output omits
 endpoint values and service internals. The ownership and executor requirements
 are documented in [`docs/client-core.md`](docs/client-core.md).
+The native Tokio UDP layer now implements the C# packet buffers and throttle
+encoding plus bounded socket receive, coordination, and single-writer tasks.
+It assigns wrapping protocol sequences, aggregates and consumes ACKs, retries
+reliable packets with duplicate suppression, preserves zerocoding and the
+1,200-byte MTU contract, applies independent task/texture/asset token buckets,
+and exposes payload-free transport statistics. All queues, peer state,
+zerocode expansion, ACK state, and reliable windows have explicit limits;
+linked cancellation and final drop release every socket task. The executor,
+wire, backpressure, retry, and security contracts are documented in
+[`docs/udp-transport.md`](docs/udp-transport.md).