fix(antigravity): a pending shell approval reads as working, plus a reattach test

Review round: the footer hint is drawn only at rest, so nothing arms the idle check while the Run this command list is up. The stock.ts comment, wiki, changeset and test now say a pending approval shows as working until answered, and the test pins busy during the confirmation. Adds the antigravity copy of the reattached-pane settle test, and updates the promptGlyph comment and the fixture header.

docs/wiki/Agent-CLIs.md

@@ -192,7 +192,8 @@ to it as well.
 - **At rest the footer hint is the idle mark.** The composer's `>` is no good for that, since
   the submitted prompt is echoed as `> <text>` as well. `? for shortcuts` is drawn only at
   rest, and the turn's last repaint carries it. A shell call that waits for approval replaces
-  the composer, so the tab reads as idle (waiting on you) until you answer.
+  the composer and the footer hint is not drawn there, so the tab keeps reading as working
+  until you answer.
 
 ### Pi