fix: align mentor header right-side icons with other pages

Remove the stale body[data-active-view="mentorView"] .app-page-context
override from the mentor page stylesheet. It was added to widen the shell
title slot for the mentor subtitle, but the shared shell owner
(.main .app-header .app-page-context) already drives that slot with higher
specificity, so the page override was dead and only left a page-scoped rule
on a shared shell element. Deleting it lets mentor reuse the same canonical
shell header as every other page, keeping the right-side header actions
flush with the right edge.

Co-authored-by: multica-agent <github@multica.ai>

app/frontend/pages/mentor/foundation.css

@@ -1,17 +1,5 @@
 /* Canonical CSS owner: mentor. Historical layers consolidated 2026-08-02. */
 
-body[data-active-view="mentorView"] .app-page-context {
-  max-width: 560px;
-  min-width: 180px;
-  overflow: visible;
-}
-
-body[data-active-view="mentorView"] .app-page-context span {
-  overflow: visible;
-  white-space: normal;
-  text-overflow: unset;
-}
-
 #mentorView.workspace-view {
   --qp-bg-header: #F5F6F7;
   --qp-bg-sidebar: #FFFFFF;