fix(ui): design-system consistency — typography, borders, admin IA, search removal

- typography: font-semibold/font-medium → font-bold throughout (card, dialog, empty-state, notification-bell, quiz-experience, questions-panel, profile-manage)
- borders: border → border-2 for content containers (leaderboard error, notifications page, quiz pass screen, quiz option tiles, learning-panel error)
- admin IA: remove Card-in-SectionPanel nesting from announce-panel, challenges-panel, physical-orders-panel; SectionPanel gains optional actions slot
- announce-panel: flat composer + live preview; history as flat list; cancel-edit button
- lockout: raw textarea → Textarea design-system component
- global-search: delete component and all references (feature removed)
- progress.tsx: dir="ltr" for correct RTL fill direction; remove rtl:me-auto

frontend/src/components/notification-bell.tsx

@@ -64,7 +64,7 @@ export function NotificationBell() {
         <div dir="rtl" className="text-start">
           <div className="flex items-center justify-between gap-3 border-b border-border px-3 py-2.5">
             <div className="min-w-0">
-              <p className="text-sm font-semibold">اعلان‌ها</p>
+              <p className="text-sm font-bold">اعلان‌ها</p>
               <p className="text-[11px] text-muted-foreground">
                 {unread > 0 ? `${unread} خوانده‌نشده` : "همه خوانده شده"}
               </p>
@@ -133,7 +133,7 @@ export function NotificationBell() {
           <button
             type="button"
             onClick={() => router.push("/notifications")}
-            className="w-full border-t border-border bg-muted/40 py-2.5 text-xs font-semibold text-primary hover:bg-muted"
+            className="w-full border-t border-border bg-muted/40 py-2.5 text-xs font-bold text-primary hover:bg-muted"
           >
             مشاهده همه اعلان‌ها
           </button>