fix: base64 stack overflow and Monaco editor error handling

- Process bytes in chunks in encodeBase64() to avoid call stack overflow on large files
- Add Monaco loader configuration for bundled assets
- Add loading state to Editor components
- Show actual token in Python example (enables Ctrl+A copy)
- Use bytes literal in set_file example

Author: adrgs

frontend/src/lib/base64.ts

@@ -1,9 +1,17 @@
 /**
  * Encode a string to base64
+ * Processes bytes in chunks to avoid call stack overflow with large data
  */
 export function encodeBase64(str: string): string {
   const bytes = new TextEncoder().encode(str);
-  return btoa(String.fromCharCode(...bytes));
+  // Process in chunks to avoid call stack overflow with spread operator
+  const CHUNK_SIZE = 0x8000; // 32KB chunks
+  let binary = "";
+  for (let i = 0; i < bytes.length; i += CHUNK_SIZE) {
+    const chunk = bytes.subarray(i, i + CHUNK_SIZE);
+    binary += String.fromCharCode.apply(null, chunk as unknown as number[]);
+  }
+  return btoa(binary);
 }
 
 /**

frontend/src/main.tsx

@@ -6,10 +6,16 @@ import { ReactQueryDevtools } from "@tanstack/react-query-devtools";
 import { BrowserRouter } from "react-router-dom";
 import { Toaster } from "sonner";
 import * as Sentry from "@sentry/react";
+import { loader } from "@monaco-editor/react";
 import App from "./App";
 import "./index.css";
 import "flag-icons/css/flag-icons.min.css";
 
+// Configure Monaco loader to use bundled assets
+loader.config({
+  "vs/nls": { availableLanguages: { "*": "en" } },
+});
+
 // Initialize Sentry for error tracking (if DSN is configured at runtime)
 // Config is injected into index.html by the backend at runtime
 declare global {

frontend/src/pages/RequestsPage.tsx

@@ -29,7 +29,7 @@ request = repo.get_http_request()
 print(request.method, request.path, request.headers)
 
 # Set a custom HTTP response
-repo.set_file("index.html", "<h1>Hello from RequestRepo!</h1>", status_code=200)
+repo.set_file("index.html", b"<h1>Hello from RequestRepo!</h1>", status_code=200)
 
 # Add DNS records
 repo.add_dns("*", "A", "1.2.3.4")  # Wildcard for all sub-subdomains
@@ -165,10 +165,9 @@ export function RequestsPage() {
                 theme={resolvedTheme === "dark" ? "vs-dark" : "light"}
                 value={PYTHON_EXAMPLE.replace(
                   /TOKEN_HERE/g,
-                  session?.token
-                    ? "********************************"
-                    : "<your_token>",
+                  session?.token || "<your_token>",
                 ).replace(/SUBDOMAIN_HERE/g, subdomain)}
+                loading={<div className="p-4 text-default-500">Loading editor...</div>}
                 options={{
                   readOnly: true,
                   minimap: { enabled: false },

frontend/src/pages/ResponseEditorPage.tsx

@@ -358,6 +358,7 @@ export function ResponseEditorPage() {
               theme={resolvedTheme === "dark" ? "vs-dark" : "light"}
               value={content}
               onChange={(value) => setContent(value ?? "")}
+              loading={<div className="p-4 text-default-500">Loading editor...</div>}
               options={{
                 minimap: { enabled: false },
                 fontSize: 13,