fix: TopNav shows actual tier from backend + complete useUserUsage type

Bug: TopNav read tier from session.user_metadata.tier (stale JWT).
When admin bumps a user to Enterprise, the JWT doesn't update until
re-login. So TopNav still showed 'Free Plan' even after upgrade.

Fix: TopNav now uses useUserUsage hook (GET /users/usage) which reads
the actual tier from user_profiles table. Changes reflect immediately
after admin dashboard tier update.

Also: added repositories and features to useUserUsage return type
to match the actual backend response shape.

Author: DevanshuNEU

frontend/src/components/dashboard/TopNav.tsx

@@ -1,6 +1,6 @@
 import { Link } from 'react-router-dom'
 import { useAuth } from '../../contexts/AuthContext'
-import { TIER_FUNCTION_LIMITS, type TierName } from '../../config/api'
+import { useUserUsage } from '../../hooks/useCachedQuery'
 import { Menu, Search, Github, Sun, Moon, LogOut, Settings, BookOpen, ExternalLink } from 'lucide-react'
 import { useTheme } from 'next-themes'
 import { Button } from '@/components/ui/button'
@@ -25,9 +25,9 @@ export function TopNav({ onToggleSidebar, sidebarCollapsed, onOpenCommandPalette
 
   const userEmail = session?.user?.email || 'User'
   const userInitial = userEmail.charAt(0).toUpperCase()
-  const rawTier = session?.user?.user_metadata?.tier as string
-  const userTier: TierName = rawTier && rawTier in TIER_FUNCTION_LIMITS ? (rawTier as TierName) : 'free'
-  const tierLabel = `${userTier.charAt(0).toUpperCase()}${userTier.slice(1)} Plan`
+  const { data: usage } = useUserUsage(session?.access_token, session?.user?.id)
+  const tier = usage?.tier || 'free'
+  const tierLabel = `${tier.charAt(0).toUpperCase()}${tier.slice(1)} Plan`
 
   const toggleTheme = () => {
     setTheme(theme === 'dark' ? 'light' : 'dark')

frontend/src/hooks/useCachedQuery.ts

@@ -199,11 +199,20 @@ export function useUserUsage(apiKey: string | undefined, userId?: string) {
       const data = await fetchWithAuth(`${API_URL}/users/usage`, apiKey!)
       return data as {
         tier: string
+        repositories: {
+          current: number
+          limit: number
+          display: string
+        }
         limits: {
           max_files_per_repo: number
           max_functions_per_repo: number
           playground_searches_per_day: number | null
         }
+        features: {
+          priority_indexing: boolean
+          mcp_access: boolean
+        }
       }
     },
     enabled: !!apiKey,