Catppuccin Mocha campaign template (default) and archive variant, kept
in sync in the database; system e-mail header/footer overridden via
--static-dir from a ConfigMap. PNG logo for mail clients. Tested in
Mailpit (desktop, phone width; 87% CSS support, rest inlined).
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
