fix: replace hardcoded 'Free Plan' with dynamic tier label in TopNav

Reads tier from session.user.user_metadata.tier (set by Supabase JWT).
Capitalizes first letter: 'free' -> 'Free Plan', 'pro' -> 'Pro Plan'.
Falls back to 'Free Plan' when tier is not set.

Previously showed 'Free Plan' for all users including Pro and Enterprise.

Author: DevanshuNEU

frontend/src/components/dashboard/TopNav.tsx

@@ -24,6 +24,8 @@ export function TopNav({ onToggleSidebar, sidebarCollapsed, onOpenCommandPalette
 
   const userEmail = session?.user?.email || 'User'
   const userInitial = userEmail.charAt(0).toUpperCase()
+  const userTier = (session?.user?.user_metadata?.tier as string) || 'free'
+  const tierLabel = `${userTier.charAt(0).toUpperCase()}${userTier.slice(1)} Plan`
 
   const toggleTheme = () => {
     setTheme(theme === 'dark' ? 'light' : 'dark')
@@ -97,7 +99,7 @@ export function TopNav({ onToggleSidebar, sidebarCollapsed, onOpenCommandPalette
               <DropdownMenuLabel className="font-normal">
                 <div className="flex flex-col space-y-1">
                   <p className="text-sm font-medium truncate">{userEmail}</p>
-                  <p className="text-xs text-muted-foreground">Free Plan</p>
+                  <p className="text-xs text-muted-foreground">{tierLabel}</p>
                 </div>
               </DropdownMenuLabel>
               <DropdownMenuSeparator />