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/listmonk.yml.j2

@@ -39,6 +39,7 @@ spec:
         app.kubernetes.io/component: app
       annotations:
         checksum/secret: {{ lookup('ansible.builtin.template', 'secret.yml.j2') | hash('sha256') }}
+        checksum/email: {{ lookup('ansible.builtin.template', 'email-configmap.yml.j2') | hash('sha256') }}
     spec:
       affinity: {{ listmonk_affinity | to_json }}
       containers:
@@ -47,14 +48,15 @@ spec:
           imagePullPolicy: {{ listmonk_image_pull_policy }}
           # --config '' : configuration comes from the environment only.
           # --install --idempotent only installs into an empty database;
-          # --upgrade runs migrations after an image bump.
+          # --upgrade runs migrations after an image bump. --static-dir
+          # overlays the eom.dev system e-mail header/footer (base.html).
           command:
             - sh
             - -c
             - >-
               ./listmonk --install --idempotent --yes --config '' &&
               ./listmonk --upgrade --yes --config '' &&
-              exec ./listmonk --config ''
+              exec ./listmonk --config '' --static-dir /listmonk/static-eom
           env:
             - name: TZ
               value: America/New_York
@@ -97,7 +99,13 @@ spec:
           volumeMounts:
             - name: uploads
               mountPath: /listmonk/uploads
+            - name: email-templates
+              mountPath: /listmonk/static-eom/email-templates
+              readOnly: true
       volumes:
+        - name: email-templates
+          configMap:
+            name: {{ listmonk_name }}-email-templates
         - name: uploads
           persistentVolumeClaim:
             claimName: {{ listmonk_name }}-uploads