feat: validate whether geeqie is installed

random_file_picker/openers.py

@@ -1,8 +1,17 @@
 import os
 import pathlib
+import shutil
 import subprocess
 
 
+def is_geeqie_available() -> bool:
+    """
+    Check if the Geeqie image viewer is available on the system.
+
+    :return: True if Geeqie is available, False otherwise.
+    """
+    return shutil.which("geeqie") is not None
+
 def open_file_with_default_app(file_path: pathlib.Path) -> bool:
     """
     Open the specified file path with the default application associated with its file type.