fix: HMR websocket connection with VITE_HOST=0.0.0.0

Author: sreya

vite.config.ts

@@ -17,7 +17,7 @@ const previewPort = Number(process.env.MUX_VITE_PREVIEW_PORT ?? "4173");
 // Allow localhost, 127.0.0.1, and all *.coder domains
 // When host is 0.0.0.0, allow all hosts for remote access
 const allowedHosts = devServerHost === "0.0.0.0" 
-  ? "all"
+  ? ["localhost", "127.0.0.1", "mux.coder", ".coder"]
   : ["localhost", "127.0.0.1", ".coder"];
 
 const alias: Record<string, string> = {
@@ -125,8 +125,10 @@ export default defineConfig(({ mode }) => ({
     },	
     hmr: {
       // Configure HMR to use the correct host for remote access
-      host: devServerHost,
-      port: devServerPort,
+      // When server binds to 0.0.0.0, clients should connect via their actual hostname
+      // Use clientPort to ensure HMR connects through the right port
+      host: devServerHost === "0.0.0.0" ? undefined : devServerHost,
+      clientPort: devServerPort,
       protocol: "ws",
     },
   },