feat: enhance admin layout with navigation and return link; add name field for sign-up in login

src/routes/(game)/login/+page.svelte

@@ -5,6 +5,7 @@
 	export let form: ActionData;
 
 	let isSignUp = false;
+	let name = '';
 	let email = '';
 	let password = '';
 	let confirmPassword = '';
@@ -12,6 +13,7 @@
 
 	const handleToggle = () => {
 		isSignUp = !isSignUp;
+		name = '';
 		email = '';
 		password = '';
 		confirmPassword = '';
@@ -55,6 +57,24 @@
 					}}
 					class="space-y-6"
 				>
+					<!-- Name Field (Sign Up Only) -->
+					{#if isSignUp}
+						<div>
+							<label for="name" class="block text-sm font-semibold uppercase tracking-[0.2em] text-amber-100">
+								Nom
+							</label>
+							<input
+								id="name"
+								type="text"
+								name="name"
+								bind:value={name}
+								required
+								placeholder="Votre nom"
+								class="mt-3 w-full rounded-lg border border-white/10 bg-white/5 px-4 py-3 text-white placeholder-slate-500 transition focus:border-amber-300 focus:outline-none focus:ring-2 focus:ring-amber-300/30"
+							/>
+						</div>
+					{/if}
+
 					<!-- Email Field -->
 					<div>
 						<label for="email" class="block text-sm font-semibold uppercase tracking-[0.2em] text-amber-100">