Connect to dispatcher only via WS (#57)

* chore: cleanup

* Add WebSocket dispatcher connection for Node.js and CF Worker

* Update dispatcher docs for WebSocket dispatch

* Add README with project overview and usage docs

* Replace fixed 30-min dispatcher reconnect with exponential backoff

* Remove Queue and RPC dispatcher fallbacks, use DO WebSocket only

* Fix TranscriberProxy tests: add dispatcher config to mock

Author: rpurdel