[cleanup] make loading prompt look nice and add link to source code

src/components/Footer.tsx

···
       >
         <strong>@noob.quest</strong>
       </a>{' '}
-      with hate 💔
+      with hate 💔 | 
+      <a
+        href="https://tangled.sh/@noob.quest/atproto-migrator/"
+        target="_blank"
+        rel="noopener noreferrer"
+        className="footer-link"
+      >
+        <strong> source code</strong>
+      </a>
     </footer>
   );
 } 

src/styles/App.css

···
   display: flex;
   align-items: center;
   justify-content: center;
+  min-height: 100vh;
+  padding: 1rem;
 }
 
 .loading-text {
   font-size: 1.25rem;
   color: var(--text-color);
+  background-color: var(--white);
+  padding: 1.5rem 2rem;
+  border-radius: 0.5rem;
+  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
+  display: flex;
+  align-items: center;
+  gap: 0.75rem;
+}
+
+.loading-text::before {
+  content: "";
+  width: 1.5rem;
+  height: 1.5rem;
+  border: 2px solid var(--primary-color);
+  border-right-color: transparent;
+  border-radius: 50%;
+  animation: spin 1s linear infinite;
+}
+
+@keyframes spin {
+  to {
+    transform: rotate(360deg);
+  }
 }
 
 /* Footer styles */