errors : Add program ending function

Add a function that quits the program using sys.exit.
This is useful when we enconter a fatal error.

src/unisync/defaults.py

@@ -1,4 +1,4 @@
-# copyright (c) 2026 paul retourné
+# Copyright (c) 2026 paul retourné
 # spdx-license-identifier: gpl-3.0-or-later
 
 from pathlib import Path

src/unisync/errors.py

@@ -1,6 +1,9 @@
 # Copyright (C) 2025-2026 Paul Retourné
 # SPDX-License-Identifier: GPL-3.0-or-later
 
+from typing import NoReturn
+import sys
+
 class RemoteMountedError(Exception):
     pass
 
@@ -12,3 +15,7 @@ class UnknownSSHError(Exception):
 
 class FatalSyncError(Exception):
     pass
+
+def unisync_exit_fatal(reason:str) -> NoReturn:
+    print(reason)
+    sys.exit(1)

src/unisync/paths.py

@@ -73,9 +73,9 @@ class PathsManager:
             try:
                 paths = self.user_select_files()
                 break
-            except subprocess.TimeoutExpired as e:
+            except subprocess.TimeoutExpired:
                 if input("Timeout expired do you want to retry (y/n): ") != "y":
-                    raise e
+                    raise
         self.write_new_paths(paths)
 
     def get_paths_to_sync(self) -> list[str]: