feat: implement XML extraction utilities and enhance feature handling

- Introduced a new xml-extractor module with functions for XML parsing, including escaping/unescaping XML characters, extracting sections and elements, and managing implemented features.
- Added functionality to add, remove, update, and check for implemented features in the app_spec.txt file.
- Enhanced the create and update feature handlers to check for duplicate titles and trigger synchronization with app_spec.txt on status changes.
- Updated tests to cover new XML extraction utilities and feature handling logic, ensuring robust functionality and reliability.

apps/server/src/lib/app-spec-format.ts

@@ -13,7 +13,7 @@ export { specOutputSchema } from '@automaker/types';
  * Escape special XML characters
  * Handles undefined/null values by converting them to empty strings
  */
-function escapeXml(str: string | undefined | null): string {
+export function escapeXml(str: string | undefined | null): string {
   if (str == null) {
     return '';
   }