add not found page

internal/ui/pages/public_notfound.templ

@@ -0,0 +1,18 @@
+package pages
+
+import "git.juancwu.dev/juancwu/budgit/internal/ui/layouts"
+
+templ NotFound() {
+	@layouts.Base() {
+		<div class="min-h-screen flex items-center justify-center">
+			<div class="text-center">
+				<h1 class="text-8xl font-bold text-muted-foreground/30 mb-4">404</h1>
+				<h2 class="text-2xl font-semibold mb-2">Page Not Found</h2>
+				<p class="text-muted-foreground mb-8">The page you are looking for does not exist.</p>
+				<a href="/" class="text-primary hover:underline">
+					← Back to Home
+				</a>
+			</div>
+		</div>
+	}
+}