feat: enhance webhook settings UI and security: Mostly working, just final post not functioning

- Add CSS styles for token URL input and hints
- Implement safe data attribute parsing in settings.js
- Refactor room fetching logic to use promise chains and auto-fetch on load
- Display full webhook URLs in the settings UI instead of raw tokens
- Generate URL-safe base64 tokens to prevent encoding issues
- Add #[PublicPage] attribute to WebhookController for unauthenticated delivery
- Filter out internal Nextcloud Talk system rooms from the room picker
- Add OCS-ApiRequest header to bot API requests
- Sanitize data attributes in templates to prevent XSS

templates/adminSettings.php

@@ -16,8 +16,8 @@
 
 <!-- Config data passed to JS via data attributes -->
 <div id="nc-config-data"
-     data-configured-rooms="<?= json_encode($rooms ?? []) ?>"
-     data-auth-tokens="<?= json_encode($authTokens ?? []) ?>"
+     data-configured-rooms="<?= htmlspecialchars(json_encode($rooms ?? []), ENT_QUOTES, 'UTF-8') ?>"
+     data-auth-tokens="<?= htmlspecialchars(json_encode($authTokens ?? []), ENT_QUOTES, 'UTF-8') ?>"
      style="display:none;">
 </div>