Fix websocket server functions and add an example (#4107)

* Fix websocket server function

* Add websocket test

* add a websocket example

* fix clippy

Cargo.toml

@@ -109,6 +109,7 @@ members = [
     "examples/fullstack-streaming",
     "examples/fullstack-desktop",
     "examples/fullstack-auth",
+    "examples/fullstack-websockets",
 
     # Playwright tests
     "packages/playwright-tests/liveview",