Run the input-method scripts with the system Python

A bare python resolves through PATH, so a mise, pyenv or venv interpreter
could run them without the system's PyGObject.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

bin/omarchy-input-method

@@ -18,5 +18,5 @@ if [[ ${1:-} == "cycle" ]]; then
     exit 1
   fi
 else
-  python "$OMARCHY_PATH/default/input-methods/configure.py" "$@"
+  /usr/bin/python3 "$OMARCHY_PATH/default/input-methods/configure.py" "$@"
 fi