Merge branch 'main' of https://git.research.dezeeuw.ca/hermes/flares

Add backup/restore mechanism to prevent plugin loss on update:
- Backs up plugins to temp location before update extraction
- Restores plugins after cleanup completes
- Each plugin preserved as-is (no uninstallation logic needed)
- Temp backups cleaned up automatically after successful restore

updater.py

@@ -706,6 +706,11 @@ def finish_update_if_needed(platform_name: str, app_name: str, cfg_path: str, fi
 
     print("Finishing update...")
 
+    # 0. Backup plugins BEFORE we do anything (Issue #113)
+    target_base = get_app_dir()
+    if os.path.exists(target_base):
+        _backup_plugins(platform_name, app_name, target_base, None)
+
     # 1. Reset welcome dialog config flag
     update_cfg = configparser.ConfigParser()
     try: