fix: Remove hidden attributes from h-app microformat

h-app was invisible to IndieAuth parsers due to hidden and
aria-hidden attributes, preventing proper client discovery.

- Remove hidden and aria-hidden="true" from h-app div
- Update version to 0.7.1
- Update CHANGELOG with fix details

This provides backward compatibility for IndieAuth services
that rely on h-app microformat parsing.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

templates/base.html

@@ -46,7 +46,7 @@
     <p>StarPunk v{{ config.get('VERSION', '0.5.0') }}</p>
 
     <!-- IndieAuth client discovery (h-app microformats) -->
-    <div class="h-app" hidden aria-hidden="true">
+    <div class="h-app">
       <a href="{{ config.SITE_URL }}" class="u-url p-name">{{ config.get('SITE_NAME', 'StarPunk') }}</a>
     </div>
   </footer>