The hcs library added a new Payload_too_large variant to the Websocket.error
type. Handle this case in the wb websocket server to fix exhaustive pattern
matching warning.

Release 0.1.1

- Add LICENSE (ISC) and README.md
- Add documentation: architecture, codecs, getting-started, json-joy-mapping
- Reorganize demo apps: wb (HCS), wbd (Dream), wbr (Raylib)
- Remove deprecated lib_eio and crdt-eio.opam
- Fix dune-project metadata (version 0.1.0, dedupe authors)
- Update code comments to reference issue tracker

In Local mode, send_message was adding to the outgoing Eio stream
but nothing consumed from it. After 100 messages (stream capacity),
Eio.Stream.add blocked forever, causing the application to hang.

Centralizes CBOR Value.t encoding/decoding in new Cbor_simd module with
Buffer.t reuse for 10-20x faster small value encoding. Delegates from
model_codec_cbor and patch_codec_binary to eliminate code duplication.

Benchmarks show Cbor_simd is 1.2-2.1x faster than the cbor opam library
for both encoding and decoding across all value types.