Test Shortcut Propagation

Add targeted tests whenever keyboard shortcut logic changes to prevent accidental shortcut/event leakage.

Requirements:

• Verify shortcut suspension lifecycle: if your code uses a suspension mechanism (e.g., suspendShortcuts() + areShortcutsSuspended()), include a unit test that proves shortcuts remain inactive until all suspensions are released.
• Verify DOM event routing: if a matched keydown should only be handled by the shortcut layer, add a test that the keydown does not reach other UI handlers (e.g., textarea/chat input), reflecting the implementation detail that uses stopImmediatePropagation().

Example test assertions (shape):

// 1) suspension lifecycle
expect(areShortcutsSuspended()).toBe(true);
// simulate keydown(s) that would normally trigger shortcut
// assert handlers were not called

// 2) propagation isolation
// render textarea/chat input with its own keydown handler
// fire keydown for the shortcut
// assert the textarea handler was not invoked