feat: add n8n to dashboard sidebar

dashboard/frontend/src/components/Sidebar.svelte

@@ -31,6 +31,7 @@
     { label: "Gitea Web", port: 3300, icon: "git", external: true },
     { label: "Stirling PDF", port: 8030, icon: "pdf", external: true },
     { label: "Vaultwarden", port: 8222, icon: "lock", external: true },
+    { label: "n8n", port: 5678, icon: "n8n", external: true },
     { label: "Speedtest", port: 8080, icon: "speedtest", external: true },
   ];
 
@@ -140,6 +141,8 @@
               <svg class="w-[16px] h-[16px]" fill="none" viewBox="0 0 24 24" stroke="currentColor" stroke-width="1.8"><path stroke-linecap="round" stroke-linejoin="round" d="M12 15v2m-6 4h12a2 2 0 002-2v-6a2 2 0 00-2-2H6a2 2 0 00-2 2v6a2 2 0 002 2zm10-10V7a4 4 0 00-8 0v4h8z" /></svg>
             {:else if item.icon === "speedtest"}
               <svg class="w-[16px] h-[16px]" fill="none" viewBox="0 0 24 24" stroke="currentColor" stroke-width="1.8"><path stroke-linecap="round" stroke-linejoin="round" d="M13 10V3L4 14h7v7l9-11h-7z" /></svg>
+            {:else if item.icon === "n8n"}
+              <svg class="w-[16px] h-[16px]" fill="none" viewBox="0 0 24 24" stroke="currentColor" stroke-width="1.8"><path stroke-linecap="round" stroke-linejoin="round" d="M4 6h16M4 12h16M4 18h16" /><circle cx="8" cy="6" r="1.5" fill="currentColor"/><circle cx="16" cy="12" r="1.5" fill="currentColor"/><circle cx="10" cy="18" r="1.5" fill="currentColor"/></svg>
             {/if}
           </span>
           {item.label}