Style newsletters and system e-mails like www.eom.dev

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>

templates/configure.sql.j2

@@ -168,6 +168,40 @@ WITH ur AS (
 SELECT count(*) FROM up;
 {% endfor %}
 
+{#- Campaign templates (templates/email/campaign.html.j2): created by name,
+    body kept in sync, and the main one is the default for new campaigns. #}
+{%- set email_templates = [
+  (listmonk_email_template_name, lookup('ansible.builtin.template', 'email/campaign.html.j2', template_vars={'archive': false})),
+  (listmonk_email_archive_template_name, lookup('ansible.builtin.template', 'email/campaign.html.j2', template_vars={'archive': true})),
+] %}
+{% for name, body in email_templates %}
+WITH ins AS (
+  INSERT INTO templates (name, type, subject, body)
+  SELECT {{ q(name) }}, 'campaign', '{{ '{{' }} .Campaign.Subject {{ '}}' }}', {{ q(body) }}
+  WHERE NOT EXISTS (SELECT 1 FROM templates WHERE name = {{ q(name) }} AND type = 'campaign')
+  RETURNING id
+)
+SELECT count(*) FROM ins;
+WITH upd AS (
+  UPDATE templates SET body = {{ q(body) }}, updated_at = NOW()
+  WHERE name = {{ q(name) }} AND type = 'campaign' AND body IS DISTINCT FROM {{ q(body) }}
+  RETURNING id
+)
+SELECT count(*) FROM upd;
+{% endfor %}
+WITH unset AS (
+  UPDATE templates SET is_default = false
+  WHERE is_default AND NOT (name = {{ q(listmonk_email_template_name) }} AND type = 'campaign')
+  RETURNING id
+)
+SELECT count(*) FROM unset;
+WITH setd AS (
+  UPDATE templates SET is_default = true
+  WHERE id = (SELECT min(id) FROM templates WHERE name = {{ q(listmonk_email_template_name) }} AND type = 'campaign') AND NOT is_default
+  RETURNING id
+)
+SELECT count(*) FROM setd;
+
 {% if listmonk_remove_sample_data | bool %}
 WITH del AS (
   DELETE FROM campaigns