Summary

cc: #1088
cc: #1138

• Added defineWebSocketRoute utility function to simplify WebSocket route definitions
• Added WebSocketRouteDefinition interface for type-safe WebSocket route configuration
• Exported new utilities from main index.ts

Description

This PR introduces a new defineWebSocketRoute function that provides a consistent API pattern with defineRoute for defining WebSocket endpoints. This makes it easier to create WebSocket routes as plugins that can be registered with app.register().

Example usage:

import { defineWebSocketRoute } from "h3";

export const webhook = defineWebSocketRoute({
  route: "/api/webhook",
  websocket: {
    open: (peer) => {
      console.log("WebSocket connected:", peer.id);
      peer.send("Welcome\!");
    },
    message: (peer, message) => {
      console.log("Incoming message:", message);
      peer.send(`Received: ${message}`);
    },
    close: (peer) => {
      console.log("WebSocket closed:", peer.id);
    },
  }
});

// Register with app
app.register(webhook);

Test plan

• Test WebSocket route registration with app.register()
• Verify WebSocket upgrade works correctly
• Test with different route patterns
• Ensure backwards compatibility with existing WebSocket handler methods