feat(web): add WebSocket transport for message event streaming with SSE fallback (#764)

* feat: add websocket message stream transport

* fix: avoid false missing session directories in sidebar

* fix: re-probe project root session directories

* refactor: use button group for message stream transport

* fix: resolve chat input hook dependency warning

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Co-authored-by: Bohdan Triapitsyn <artmore@protonmail.com>

packages/web/server/lib/event-stream/index.js

@@ -0,0 +1,13 @@
+export {
+  MESSAGE_STREAM_GLOBAL_WS_PATH,
+  MESSAGE_STREAM_DIRECTORY_WS_PATH,
+  MESSAGE_STREAM_WS_HEARTBEAT_INTERVAL_MS,
+  parseSseEventEnvelope,
+  sendMessageStreamWsFrame,
+  sendMessageStreamWsEvent,
+} from './protocol.js';
+
+export {
+  createGlobalUiEventBroadcaster,
+  createMessageStreamWsRuntime,
+} from './runtime.js';