ui: polish navbar visibility and home page greetings

Hide My Schedule link from admin users (they have dashboard instead).
Add 60+ randomized greeting strings split between returning and new users.
Update dev script admin seed name.

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

frontend/src/lib/components/layout/NavBar.svelte

@@ -8,7 +8,7 @@
 	const links = [
 		{ href: '/', label: 'Home', showWhen: 'always', width: 'w-12' },
 		{ href: '/prices', label: 'Price List', showWhen: 'guest', width: 'w-20' },
-		{ href: '/schedule', label: 'My Schedule', showWhen: 'auth', width: 'w-24' },
+		{ href: '/schedule', label: 'My Schedule', showWhen: 'auth-not-admin', width: 'w-24' },
 		{ href: '/book', label: 'Book an appointment', showWhen: 'auth', width: 'w-36' },
 		{ href: '/portfolio', label: 'Portfolio', showWhen: 'always', width: 'w-20' },
 		{ href: '/admin', label: 'Admin Dashboard', showWhen: 'admin', width: 'w-28' },
@@ -40,13 +40,18 @@
 		if (link.showWhen === 'always') return true;
 		if (link.showWhen === 'guest' && !authStore.isAuthenticated) return true;
 		if (link.showWhen === 'auth' && authStore.isAuthenticated) return true;
+		if (
+			link.showWhen === 'auth-not-admin' &&
+			authStore.isAuthenticated &&
+			authStore.currentUser?.role !== 'admin'
+		)
+			return true;
 		if (link.showWhen === 'admin' && authStore.currentUser?.role === 'admin') return true;
 		return false;
 	};
 
 	// Derived values for auth state - ensures reactivity
 	let isAuthenticated = $derived(authStore.isAuthenticated);
-	let currentUserRole = $derived(authStore.currentUser?.role);
 	let isLoading = $derived(authStore.isLoading);
 </script>