release: v1.2.1 — login captcha, docs site, and bug fixes

Add slider captcha for web login, VitePress documentation on GitHub Pages,
and fixes for gallery delete refresh, pagination jump, and copy-format persistence.

.github/workflows/ci.yml

@@ -37,3 +37,6 @@ jobs:
 
       - name: Test
         run: npm run test
+
+      - name: Build docs
+        run: npm run docs:build