Add REST API endpoints for repo folder listing and page pushing

- Implemented `GET /repo-folders` to list available sub-folders in the configured repository.
- Added `POST /push` to push a single page to the repository.
- Introduced `POST /push-all` to push all synced pages back to the repository.
- Enhanced `oribi_sync_rest_sync` to push local changes after pulling, except during dry runs.
- Created `oribi_sync_push_page` and `oribi_sync_push_all` functions to handle page pushing logic.
- Updated post meta on successful pushes to track last push time and SHA.
- Added logging for push actions and errors.

Enhance sync engine to support theme file synchronization

- Added functionality to auto-apply changed theme files from the repository's theme directory.
- Created `oribi_sync_apply_theme_files` to handle theme file updates during sync.
- Ensured the existence of a minimal theme structure in the `ots-theme` directory.

Refactor uninstall process to clean up additional post meta

- Updated `uninstall.php` to remove new post meta related to push operations.
- Ensured comprehensive cleanup of options and metadata upon plugin uninstallation.

Introduce push client for handling page pushes to Gitea

- Created `push-client.php` to encapsulate logic for pushing pages back to the Git repository.
- Implemented conflict resolution by creating branches and opening pull requests when necessary.
- Added helper functions for authenticated API requests to Gitea.

uninstall.php

@@ -16,6 +16,7 @@ delete_option( 'oribi_sync_last_run' );
 delete_option( 'oribi_sync_log' );
 delete_option( 'oribi_sync_webhook_secret' );
 delete_option( 'oribi_sync_theme_applied' );
+delete_option( 'oribi_sync_push_log' );
 
 // Remove sync metadata from posts
 $posts = get_posts( [
@@ -28,8 +29,11 @@ $posts = get_posts( [
 
 foreach ( $posts as $post_id ) {
     delete_post_meta( $post_id, '_oribi_sync_checksum' );
+    delete_post_meta( $post_id, '_oribi_sync_git_sha' );
     delete_post_meta( $post_id, '_oribi_sync_source' );
     delete_post_meta( $post_id, '_oribi_sync_last_run' );
+    delete_post_meta( $post_id, '_oribi_sync_last_push' );
+    delete_post_meta( $post_id, '_oribi_sync_pr_url' );
 }
 
 // Clear any scheduled cron