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

frontend/src/components/AppFooter.tsx

@@ -0,0 +1,45 @@
+import React from 'react';
+import { AuthStatus } from '../lib/types';
+import { APP_VERSION } from '../version';
+import { LegalLinks } from './LegalLinks';
+
+interface AppFooterProps {
+  legal?: AuthStatus['legal'];
+  onOpenAbout: () => void;
+}
+
+export const AppFooter: React.FC<AppFooterProps> = ({ legal, onOpenAbout }) => {
+  return (
+    <footer className="hidden sm:flex shrink-0 w-full max-w-6xl mx-auto px-4 py-2 items-center justify-between text-[11px] text-faint border-t border-border/40 select-none">
+      <div className="flex items-center gap-3">
+        <button
+          type="button"
+          onClick={onOpenAbout}
+          className="font-semibold text-muted hover:text-main transition-colors cursor-pointer"
+        >
+          MindSift
+        </button>
+        <button
+          type="button"
+          onClick={onOpenAbout}
+          className="font-mono hover:text-main transition-colors cursor-pointer"
+          title="Über MindSift & Versionsdetails"
+        >
+          {APP_VERSION}
+        </button>
+        <span className="text-border">·</span>
+        <button
+          type="button"
+          onClick={onOpenAbout}
+          className="hover:text-main transition-colors cursor-pointer underline-offset-2 hover:underline"
+        >
+          Über MindSift
+        </button>
+      </div>
+
+      <div className="flex items-center gap-3">
+        <LegalLinks legal={legal} className="!text-faint gap-3" />
+      </div>
+    </footer>
+  );
+};

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 && (