Add Device > Discover menu with standalone discovery dialog

Discover dialog shows a device list with Port, Wait Time fields and a
Discover button. Selecting a device and clicking Connect (or double-
clicking) opens a credentials prompt for username/password, then
connects. The Connect dialog is reverted to its original simple form.

Co-Authored-By: Claude Opus 4.6 <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 = "0.0.0.097"
+VERSION = "0.0.0.098"
 PROPERTIES_FILE = os.path.join(os.path.dirname(os.path.abspath(__file__)), "editor.properties")
 DEFAULT_GRID_SIZE = 10
 DEFAULT_ADD_TIMESTAMP = True