feat(auth): add user profile, phone login, and account deletion

frontend/src/routes/(public)/login/+page.svelte

@@ -4,7 +4,9 @@
 	import { auth } from '$lib/stores/auth.svelte';
 
 	let mode = $state<'login' | 'register'>('login');
+	let identifier = $state('');
 	let email = $state('');
+	let phone = $state('');
 	let password = $state('');
 	let name = $state('');
 	let error = $state('');
@@ -13,12 +15,16 @@
 	async function submit(ev: Event) {
 		ev.preventDefault();
 		error = '';
+		if (mode === 'register' && !email.trim() && !phone.trim()) {
+			error = 'Укажите email или телефон';
+			return;
+		}
 		busy = true;
 		try {
 			const data =
 				mode === 'login'
-					? await authApi.login(email, password)
-					: await authApi.register(email, password, name);
+					? await authApi.login(identifier, password)
+					: await authApi.register(email, phone, password, name);
 			auth.setTokens(data.tokens);
 			auth.setUser(data.user);
 			goto('/');
@@ -43,16 +49,34 @@
 					class="border-border bg-bg-elevated text-text w-full rounded-lg border px-3 py-2"
 				/>
 			</label>
+			<label class="block">
+				<span class="text-text-muted mb-1 block text-sm">Email (необязательно)</span>
+				<input
+					bind:value={email}
+					type="email"
+					class="border-border bg-bg-elevated text-text w-full rounded-lg border px-3 py-2"
+				/>
+			</label>
+			<label class="block">
+				<span class="text-text-muted mb-1 block text-sm">Телефон (необязательно)</span>
+				<input
+					bind:value={phone}
+					type="tel"
+					placeholder="+15551234567"
+					class="border-border bg-bg-elevated text-text w-full rounded-lg border px-3 py-2"
+				/>
+			</label>
+			<p class="text-text-muted text-xs">Нужен хотя бы один из email или телефона.</p>
+		{:else}
+			<label class="block">
+				<span class="text-text-muted mb-1 block text-sm">Email или телефон</span>
+				<input
+					bind:value={identifier}
+					required
+					class="border-border bg-bg-elevated text-text w-full rounded-lg border px-3 py-2"
+				/>
+			</label>
 		{/if}
-		<label class="block">
-			<span class="text-text-muted mb-1 block text-sm">Email</span>
-			<input
-				bind:value={email}
-				type="email"
-				required
-				class="border-border bg-bg-elevated text-text w-full rounded-lg border px-3 py-2"
-			/>
-		</label>
 		<label class="block">
 			<span class="text-text-muted mb-1 block text-sm">Пароль</span>
 			<input