Duplicate components from the sheet and tree popups, with links between them

Ctrl+click picks out several boxes on the sheet, and Ctrl/Shift+click several
rows in the tree. Copies are named on from their original (Add1 -> Add2), sit
one step right and down, and keep the links that ran between the copied
components. One undo step; on a device the originals are read back in full
and the copies made there.

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 = "0.0.0.156"
+VERSION = "0.0.0.157"
 PROPERTIES_FILE = os.path.join(os.path.dirname(os.path.abspath(__file__)), "editor.properties")
 DEFAULT_GRID_SIZE = 10
 DEFAULT_ADD_TIMESTAMP = True
@@ -82,6 +82,7 @@ is_dirty = False
 current_file_path = None
 active_components_list = []   # Tracks what components are actively painted
 selected_canvas_tag = None    # Tracks the currently clicked/highlighted canvas component tag
+selected_canvas_tags = set()  # Every selected box, the one above included; Ctrl+click adds
 selected_tree_item_id = None  # Tracks the currently right-clicked Treeview item
 link_mark_element = None      # Component marked as a link endpoint via "Link Mark"
 selected_link_tag = None      # Canvas tag of the currently selected (red-highlighted) link wire