Add version chip (v0.1.0) + changelog

- version.py: __version__ = 0.1.0 + structured CHANGELOG (newest first).
- footer version chip on every page (base.html) links to /changelog.
- /changelog page renders release notes; CHANGELOG.md mirrors it.
- 0.1.0 captures the storage/SQLite/settings/suggestions/backup work.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

templates/base.html

@@ -36,6 +36,12 @@
     {% endif %}
     {% block content %}{% endblock %}
   </main>
+  <footer style="text-align:center;padding:1.5rem 0 2.25rem;">
+    <a href="{{ url_for('changelog_view') }}" title="What's new"
+       style="display:inline-block;font-size:.75rem;color:#B0A89E;text-decoration:none;border:1px solid #EDE8E2;border-radius:999px;padding:.2rem .65rem;">
+      🌙 Moon Household Budget · v{{ app_version }}
+    </a>
+  </footer>
 <script>
 document.addEventListener('DOMContentLoaded', function () {
   // Wrap all number budget-inputs with a $ prefix and format on blur