feat: implement My Account page

Add /account route showing display name (from localStorage), role badge,
session expiry decoded from JWT, and recovery PIN display with copy button.
Join and recover flows now persist display_name to localStorage via setAuth().
Feed header logout button replaced with person-icon link to /account;
logout is available from the account page.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

frontend/src/routes/feed/+page.svelte

@@ -1,6 +1,6 @@
 <script lang="ts">
 	import { goto } from '$app/navigation';
-	import { getToken, clearAuth } from '$lib/auth';
+	import { getToken } from '$lib/auth';
 	import { api } from '$lib/api';
 	import { connectSse, disconnectSse, onSseEvent } from '$lib/sse';
 	import { onMount, onDestroy } from 'svelte';
@@ -152,11 +152,7 @@
 		if (u) selectedUpload = u;
 	}
 
-	async function handleLogout() {
-		try { await api.delete('/session'); } catch { /* ignore */ }
-		clearAuth();
-		goto('/join');
-	}
+
 </script>
 
 <div class="min-h-screen bg-gray-50">
@@ -171,12 +167,15 @@
 				>
 					Hochladen
 				</a>
-				<button
-					onclick={handleLogout}
+				<a
+					href="/account"
 					class="text-sm text-gray-500 hover:text-gray-700"
+					aria-label="Mein Konto"
 				>
-					Abmelden
-				</button>
+					<svg xmlns="http://www.w3.org/2000/svg" class="h-6 w-6" fill="none" viewBox="0 0 24 24" stroke="currentColor" stroke-width="1.5">
+						<path stroke-linecap="round" stroke-linejoin="round" d="M15.75 6a3.75 3.75 0 1 1-7.5 0 3.75 3.75 0 0 1 7.5 0ZM4.501 20.118a7.5 7.5 0 0 1 14.998 0A17.933 17.933 0 0 1 12 21.75c-2.676 0-5.216-.584-7.499-1.632Z" />
+					</svg>
+				</a>
 			</div>
 		</div>