Consolidate Tray Icons OR (alternatively) Distinguish between Elevated and Unelevated Instances

# Description of the new feature/enhancement

Currently, if we have two instances of Terminal running (one elevated and one not), we get two _identical_ icons in the task bar. This can be a slight inconvenience when Terminal is set to minimize to tray, as often, it requires that we activate both windows to determine which is the one with which we actually want to interact:


An improvement could be as simple as a change of color, or a small shield badge to differentiate the two icons. Or even better, (if it's even possible) consolidate the icons into one, and allow the user to select the desired window from a context menu.

# Proposed technical implementation details (optional)

The issue names no files, tests, or entry points. Start by locating the tray-icon handling and how elevated and unelevated Terminal instances are represented, then clarify whether the accepted result is distinct icons or one consolidated icon with a window-selection menu.

Written by the indexing model from the issue text.