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>

app.py

@@ -8,6 +8,7 @@ import calendar as cal_module
 from storage import load_json, save_json
 from settings import load_settings, save_settings, SECRET_KEYS
 import txns_db
+from version import __version__ as APP_VERSION, CHANGELOG
 from categories import CATEGORIES, CATEGORY_COLORS
 from bills import load_bills, save_bills, bills_for_month, calendar_grid, get_week_num
 from sinking import (load_funds, save_funds, FUND_COLORS, monthly_needed,
@@ -167,6 +168,11 @@ def inject_unreviewed_count():
     # Fast COUNT query instead of parsing the whole transaction store per request.
     return dict(unreviewed_count=txns_db.count_unreviewed())
 
+
+@app.context_processor
+def inject_version():
+    return dict(app_version=APP_VERSION)
+
 DATA_DIR = os.environ.get("DATA_DIR", os.path.join(os.path.dirname(__file__), "data"))
 TRANSACTIONS_FILE = os.path.join(DATA_DIR, "transactions.json")
 RULES_FILE = os.path.join(DATA_DIR, "rules.json")
@@ -2878,5 +2884,10 @@ def settings_view():
                            saved=request.args.get("saved"))
 
 
+@app.route("/changelog")
+def changelog_view():
+    return render_template("changelog.html", changelog=CHANGELOG, app_version=APP_VERSION)
+
+
 if __name__ == "__main__":
     app.run(debug=os.environ.get("FLASK_DEBUG") == "1", port=5000)