Task Page Action Bar Overlay Fixes

Seen on the local stack while verifying Task 8109 (task page, waiting row, desktop 1280 and phone 400): 1. Phone: with Go withdrawn, a disabled Save now stretches across the whole bar. Give a lone Save its natural width, or hide it while there are no changes and let the reason line stand alone. 2. Desktop: the floating "1/3" queue widget at the top right sits over the task panel's maximize/close icons. Keep it clear of the panel's header controls. 3. Phone: Attach is stowed in Advanced when there are no files, so the main form gives no way to add one. Consider a compact Attach icon next to the axes. Out of scope: Go's start/reset semantics; the Task 8084/8096 hold. Done means: - Each item fixed or ruled out with a one-line reason; vitest covers what changed; a live screenshot at desktop and phone width.

Phone: a lone Save keeps its own width; a compact paperclip Attach now sits on the axes line. Desktop widget overlap ruled out (docked in flow, not reproduced). Vitest added, quick gate green, live check at 1280 and 400 done. PR #6335 queued in the lane; follow-up draft #8187.