chore: synchronize pending app/backend updates and repository hygiene

Includes current frontend and backend work in progress and removes generated artifacts from tracking to keep the repository clean for дальнейшая разработка.

Co-authored-by: Cursor <cursoragent@cursor.com>

components/nav-main.tsx

@@ -14,6 +14,7 @@ export interface NavItem {
   title: string
   url: string
   icon?: React.ReactNode
+  /** Если `undefined` — счётчик не показываем (нет данных или раздел без live-источника). */
   badge?: string
 }
 
@@ -40,7 +41,7 @@ export function NavMain({ groups }: { groups: NavGroup[] }) {
                 >
                   {item.icon}
                   <span>{item.title}</span>
-                  {item.badge && (
+                  {item.badge != null && item.badge !== "" && (
                     <span className="ml-auto text-[10.5px] font-mono tabular-nums text-sidebar-foreground/50 group-data-[collapsible=icon]:hidden">
                       {item.badge}
                     </span>