Add VERSION file and live version display on settings page

- New VERSION file at project root, starting at 0.3.0.
- config.py reads VERSION and exposes it as Config.VERSION.
- Admin settings page now renders the live version from config.
- Semantic versioning convention: MAJOR for breaking/user-facing changes,
  MINOR for new features, PATCH for bug fixes and small polish.

app.py

@@ -1444,6 +1444,7 @@ def admin_settings():
         hermes_key_masked=hermes_key_masked,
         hermes_key_set=hermes_key_set,
         hermes_key_just_generated=hermes_key_just_generated,
+        version=current_app.config['VERSION'],
     )