lib.App: Log reason for skipped completion

The shell completion setup in __run() catches every exception and
silently ignores it. If argcomplete is missing or its initialization
fails, the completion is simply not available and there is no trace
of why, even when logging is turned up to debug level.

Log the reason at debug level: one message when the argcomplete
import fails and one with the exception for any other failure.

Assisted-by: unsloth/Qwen3.8-27B-GGUF:Q4_K_M with pi.dev v0.84.2
Signed-off-by: Jan Lindemann <jan@janware.com>

src/python/jw/pkg/lib/App.py

@@ -284,8 +284,10 @@ class App:  # export
 
             argcomplete.autocomplete(self.__parser, default_completer = NoopCompleter())
 
-        except Exception:
-            pass
+        except ImportError:
+            log(DEBUG, 'argcomplete is not installed, shell completion disabled')
+        except Exception as e:
+            log(DEBUG, f'Shell completion disabled: {e}')
 
         self.__args = self.__parser.parse_args(args = argv)