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>

CHANGELOG.md

@@ -0,0 +1,15 @@
+# Changelog
+
+All notable changes to Moon Household Budget. Newest first.
+This file mirrors the structured changelog in `version.py` (shown at `/changelog`).
+
+## 0.1.0 — 2026-06-06 — First tracked release
+
+- Crash-safe data storage — saves are now atomic and a corrupted file can no longer take the app down.
+- Transactions moved to a SQLite database: faster, and safe when edited from two tabs at once. Existing transactions were migrated automatically.
+- New Settings page (⚙️) to store your Gmail login and reminder preferences securely — no passwords in the code anymore.
+- Suggestions & feedback (💡) is now reachable from every page; what you send becomes a tracked issue.
+- Bill email reminders now use the Gmail login from Settings.
+- Automatic daily backups of all your data (local for now; Backblaze cloud once a bucket is set up).
+- Fixed the Monthly view crashing on the budget total.
+- Added this version number and changelog.