feat: footer with source code link

app/globals.css

@@ -593,6 +593,58 @@ button:hover:not(:disabled) {
   font-size: 12px;
 }
 
+.footer {
+  margin-top: 8px;
+  padding: 14px 18px;
+  border: 1px solid var(--border);
+  border-radius: 14px;
+  background: var(--surface);
+  display: flex;
+  align-items: center;
+  justify-content: space-between;
+  gap: 12px;
+}
+
+.footer-left {
+  display: flex;
+  align-items: center;
+  gap: 10px;
+}
+
+.version-pill {
+  display: inline-flex;
+  align-items: center;
+  justify-content: center;
+  padding: 6px 10px;
+  border-radius: 999px;
+  font-weight: 700;
+  font-size: 12px;
+  letter-spacing: 0.03em;
+  background: var(--pill);
+  border: 1px solid var(--pill-border);
+  color: var(--pill-text);
+}
+
+.footer-link {
+  display: inline-flex;
+  align-items: center;
+  gap: 8px;
+  color: var(--ink);
+  text-decoration: none;
+  font-weight: 700;
+}
+
+.footer-link:hover {
+  color: var(--link);
+  text-decoration: underline;
+}
+
+.gitea-icon {
+  width: 26px;
+  height: 26px;
+  display: inline-block;
+}
+
 @media (max-width: 640px) {
   body {
     padding: 18px;