feat: Android download page, analysis retry and a collapsible search

- /android is a public page with the latest APK, the server address to copy
  and three install steps; linked from the sign-in screen and the profile menu
- failed audio analysis can be retried from the library page, which also shows
  the most common error; the analyzer no longer burns attempts on files that
  are missing because the disk is not mounted
- the top bar search folds into a round button and slides open on click, "/"
  or Ctrl+K

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

apps/web/src/pages/auth.module.css

@@ -161,6 +161,83 @@
   color: var(--text3);
 }
 
+.footer a {
+  color: var(--text2);
+}
+
+/* Страница Android-приложения (/android). */
+.download {
+  display: flex;
+  align-items: center;
+  gap: 14px;
+  padding: 14px 18px;
+  border-radius: var(--radius-lg);
+  background: var(--accent-fill);
+  color: #fff;
+  font-weight: 700;
+  text-decoration: none;
+  box-shadow: var(--glow);
+  transition:
+    background 0.2s,
+    transform 0.15s;
+}
+
+.download:hover {
+  background: var(--accent-fill2);
+}
+
+.download:active {
+  transform: scale(0.98);
+}
+
+.downloadMeta {
+  display: block;
+  margin-top: 2px;
+  font-size: 12px;
+  font-weight: 500;
+  opacity: 0.85;
+}
+
+.steps {
+  margin: 0;
+  padding-left: 20px;
+  display: flex;
+  flex-direction: column;
+  gap: 10px;
+  color: var(--text2);
+  font-size: 14px;
+  line-height: 1.5;
+}
+
+.server {
+  display: inline-flex;
+  align-items: center;
+  gap: 8px;
+  margin-left: 6px;
+  padding: 2px 10px;
+  border-radius: 8px;
+  border: 1px solid var(--line2);
+  background: var(--surface2);
+  color: var(--text);
+  cursor: pointer;
+}
+
+.details {
+  font-size: 12px;
+  color: var(--text3);
+}
+
+.details summary {
+  cursor: pointer;
+}
+
+.details code {
+  display: block;
+  margin-top: 6px;
+  word-break: break-all;
+  font-family: var(--font-mono);
+}
+
 .link {
   align-self: center;
 }