feat: enhance theme handling and layout components for Telegram Mini App

- Updated theme resolution logic to utilize a shared inline script for consistent theme application across routes.
- Introduced `AppShell` and `ReadyGate` components to manage app readiness and theme synchronization, improving user experience.
- Enhanced `GlobalError` and `NotFound` pages with a unified full-screen layout for better accessibility and visual consistency.
- Refactored CSS to implement safe area insets for sticky headers and content safety, ensuring proper layout on various devices.
- Added unit tests for new functionality and improved existing tests for better coverage and reliability.

webapp-next/src/components/current-duty/CurrentDutyView.tsx

@@ -340,13 +340,12 @@ export function CurrentDutyView({ onBack, openedFromPin = false }: CurrentDutyVi
           </section>
           <div
             className="rounded-lg bg-duty/10 px-3 py-2.5 flex flex-col gap-1"
-            aria-live="polite"
-            aria-atomic="true"
+            aria-label={t("current_duty.remaining_label")}
           >
             <span className="text-xs text-muted-foreground">
               {t("current_duty.remaining_label")}
             </span>
-            <span className="text-xl font-semibold text-foreground tabular-nums">
+            <span className="text-xl font-semibold text-foreground tabular-nums" aria-hidden>
               {remainingValueStr}
             </span>
             <span className="text-xs text-muted-foreground">