feat(gateway): allow webchat port override

src/cli/program.ts

@@ -214,6 +214,10 @@ Examples:
     .command("gateway")
     .description("Run the WebSocket Gateway")
     .option("--port <port>", "Port for the gateway WebSocket", "18789")
+    .option(
+      "--webchat-port <port>",
+      "Port for the loopback WebChat HTTP server (default 18788)",
+    )
     .option(
       "--token <token>",
       "Shared token required in hello.auth.token (default: CLAWDIS_GATEWAY_TOKEN env if set)",
@@ -231,6 +235,13 @@ Examples:
         defaultRuntime.error("Invalid port");
         defaultRuntime.exit(1);
       }
+      const webchatPort = opts.webchatPort
+        ? Number.parseInt(String(opts.webchatPort), 10)
+        : undefined;
+      if (webchatPort !== undefined && (Number.isNaN(webchatPort) || webchatPort <= 0)) {
+        defaultRuntime.error("Invalid webchat port");
+        defaultRuntime.exit(1);
+      }
       if (opts.force) {
         try {
           const killed = forceFreePort(port);
@@ -256,7 +267,7 @@ Examples:
         process.env.CLAWDIS_GATEWAY_TOKEN = String(opts.token);
       }
       try {
-        await startGatewayServer(port);
+        await startGatewayServer(port, { webchatPort });
       } catch (err) {
         if (err instanceof GatewayLockError) {
           defaultRuntime.error(`Gateway failed to start: ${err.message}`);