- Implemented across bootstrap.php, chat frontend, and dashboard:

Per-tier audio bitrate: Free 64, Plus 96, Pro 128 kbps.
Configurable text/voice reply threads and depth.
Registration/login-only honeypot and internal CAPTCHA.
Optional Google reCAPTCHA v2/v3 with server verification.
Archive/export support for replies and bitrate.
Dashboard controls for all settings.
Verified JavaScript, JSON, SQLite migrations, desktop/mobile UI, and 
browser console. Native PHP lint was unavailable because PHP is not 
installed.
Google implementation follows Siteverify and reCAPTCHA v3.

api/config.php

@@ -12,9 +12,22 @@ jsonResponse([
         'poll_timeout_ms' => $config['chat']['poll_timeout_ms'] ?? 12000,
         'poll_max_backoff_ms' => $config['chat']['poll_max_backoff_ms'] ?? 15000,
         'max_rendered_messages' => $config['chat']['max_rendered_messages'] ?? 500,
+        'replies_enabled' => $config['chat']['replies_enabled'] ?? true,
+        'reply_max_depth' => $config['chat']['reply_max_depth'] ?? 4,
     ],
     'ui' => $config['ui'] ?? [],
-    'security' => ['min_password_length' => $config['security']['min_password_length'] ?? 4],
+    'security' => [
+        'min_password_length' => $config['security']['min_password_length'] ?? 4,
+        'captcha' => [
+            'registration_enabled' => $config['security']['captcha']['registration_enabled'] ?? false,
+            'login_enabled' => $config['security']['captcha']['login_enabled'] ?? false,
+            'honeypot_enabled' => $config['security']['captcha']['honeypot']['enabled'] ?? true,
+            'internal_enabled' => $config['security']['captcha']['internal']['enabled'] ?? false,
+            'google_enabled' => $config['security']['captcha']['google']['enabled'] ?? false,
+            'google_version' => $config['security']['captcha']['google']['version'] ?? 'v2',
+            'google_site_key' => $config['security']['captcha']['google']['site_key'] ?? '',
+        ],
+    ],
     'colors' => ['user_palette' => $config['colors']['user_palette'] ?? []],
     'voice' => [
         'enabled' => $config['voice']['enabled'] ?? true,