Remove redo; undo rename on a device

Redo is gone in both file and device mode: the Edit menu entry, Ctrl/Cmd+Y
and Ctrl/Cmd+Shift+Z, and the redo stack. An undone step is dropped.
Undoing past the last save now leaves the saved depth unreachable, so a
new edit cannot be mistaken for the saved state.

Renames on a device are undoable: LiveRenameCommand renames back on the
device first, and warns and clears history if the device refuses.

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

app_state.py

@@ -8,7 +8,7 @@ so later rebinding would only ever be seen by the module that did it.
 import configparser
 import os
 
-VERSION = "0.0.0.152"
+VERSION = "0.0.0.153"
 PROPERTIES_FILE = os.path.join(os.path.dirname(os.path.abspath(__file__)), "editor.properties")
 DEFAULT_GRID_SIZE = 10
 DEFAULT_ADD_TIMESTAMP = True