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/ui/progress.tsx

@@ -16,12 +16,13 @@ const Progress = React.forwardRef<HTMLDivElement, ProgressProps>(
     return (
       <div
         ref={ref}
+        dir="ltr"
         className={cn("relative h-2.5 w-full overflow-hidden rounded-full bg-muted", className)}
         {...props}
       >
         <div
           className={cn(
-            "h-full rounded-full will-change-[width] rtl:me-auto",
+            "h-full rounded-full will-change-[width]",
             gradient ? "bg-primary" : "bg-primary",
             smooth
               ? "transition-[width] duration-1000 ease-[cubic-bezier(0.22,1,0.36,1)]"