Fix WebSocket connection in dev mode (bun run dev)

client/src/components/Terminal.tsx

@@ -83,9 +83,19 @@ export function Terminal({ sessionId, color, nodeId }: TerminalProps) {
     xtermRef.current = term;
     fitAddonRef.current = fitAddon;
 
-    // Connect WebSocket with small delay to allow session to be ready
+    // Connect WebSocket with small delay to allow session to be ready.
+    // Always mirror the page's protocol (ws for http, wss for https) so the
+    // browser never blocks the connection under its mixed-content policy.
+    // In dev, Vite's proxy can't relay Bun's WebSocket upgrade response, so connect
+    // directly to the backend's host/port; the default dev page is served over plain
+    // HTTP, yielding ws://. (Serving the dev page over HTTPS requires the backend to
+    // be reachable over TLS, since the browser forbids ws:// from an https:// origin.)
+    // In production (single-server) the backend serves the client itself, so reuse
+    // the current host.
     const protocol = window.location.protocol === "https:" ? "wss:" : "ws:";
-    const wsUrl = `${protocol}//${window.location.host}/ws?sessionId=${sessionId}`;
+    const wsUrl = import.meta.env.DEV
+      ? `${protocol}//${window.location.hostname}:${import.meta.env.VITE_BACKEND_PORT ?? 6968}/ws?sessionId=${sessionId}`
+      : `${protocol}//${window.location.host}/ws?sessionId=${sessionId}`;
 
     let ws: WebSocket | null = null;
     let isFirstMessage = true;

client/vite.config.ts

@@ -10,10 +10,9 @@ export default defineConfig({
         target: "http://localhost:6968",
         changeOrigin: true,
       },
-      "/ws": {
-        target: "ws://localhost:6968",
-        ws: true,
-      },
+      // NOTE: /ws is intentionally not proxied. Vite's http-proxy cannot relay
+      // Bun.serve's WebSocket upgrade response, so the client connects directly
+      // to the backend in dev (see Terminal.tsx).
     },
   },
   build: {