feat(ui): add desktop footer, legal custom link and about dialog

frontend/src/components/LegalLinks.tsx

@@ -28,7 +28,9 @@ export const LegalLinks: React.FC<LegalLinksProps> = ({ legal, className = '', c
     }))
     .filter((e) => e.url || e.hasContent);
 
-  if (entries.length === 0 && !children) return null;
+  const customHref = legal?.customLinkUrl && safeHref(legal.customLinkUrl);
+
+  if (entries.length === 0 && !children && !customHref) return null;
 
   const openText = async (type: LegalType) => {
     setError(null);
@@ -52,6 +54,16 @@ export const LegalLinks: React.FC<LegalLinksProps> = ({ legal, className = '', c
           </button>
         )
       )}
+      {customHref && (
+        <a
+          href={customHref as string}
+          target="_blank"
+          rel="noopener noreferrer"
+          className="hover:text-main underline-offset-2 hover:underline"
+        >
+          {legal?.customLinkLabel || legal?.customLinkUrl}
+        </a>
+      )}
       {children}
       {error && <span className="text-status-err">{error}</span>}
       {open && (