feat(debyltech-cloud): plain login background, empty homes for new accounts

- theming background -> backgroundColor, dropping the stock image for the
  navy theming colour.
- skeletondirectory/templatedirectory set to "" so customer accounts start
  empty instead of getting Nextcloud's sample Manual, intro video and
  Templates folder.
- The system-config compare now tells an unset key apart from an empty
  value. Both print nothing, so an intentionally empty setting was
  silently skipped.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

ansible/roles/podman/tasks/containers/debyltech/cloud.yml

@@ -524,7 +524,9 @@
   ansible.builtin.shell: |
     set -o pipefail
     occ() { podman exec -u www-data debyltech-cloud php occ "$@"; }
-    cur=$(occ config:system:get {{ item.k }} || true)
+    # An UNSET key prints nothing and exits 1 -- indistinguishable from ""
+    # by output alone, which would skip setting an intentionally empty value.
+    cur=$(occ config:system:get {{ item.k }}) || cur='<unset>'
     if [ "$cur" != {{ item.v | quote }} ]; then
       occ config:system:set {{ item.k }} --value={{ item.v | quote }} --type={{ item.t | default('string') }} >/dev/null
       echo CHANGED
@@ -540,6 +542,10 @@
     # Hour in UTC: 05:00 UTC is 01:00/00:00 Eastern, ahead of the 04:15 backup.
     - {k: maintenance_window_start, v: "5", t: integer}
     - {k: default_phone_region, v: US}
+    # New accounts -- customers above all -- start with an empty home rather
+    # than Nextcloud's sample Manual/intro video/Readme and Templates folder.
+    - {k: skeletondirectory, v: ""}
+    - {k: templatedirectory, v: ""}
     - {k: loglevel, v: "2", t: integer}
     - {k: log_rotate_size, v: "10485760", t: integer}
     - {k: mail_template_class, v: "OCA\\Debyltechmail\\Mail\\DebyltechEMailTemplate"}
@@ -605,6 +611,25 @@
 # call, so it runs only when the app's files changed or no logo is set yet.
 # `logo` is the wide wordmark on the login page; `logoheader` is the square
 # mark in the top bar, where a wordmark would shrink to illegibility.
+# Plain theming_debyltech_background instead of Nextcloud's stock blue-shapes
+# image. `background backgroundColor` is a special case in UpdateConfig.php
+# (absent from --help) that drops the image and sets backgroundMime, exactly
+# what the admin UI's "remove background image" does.
+- name: use a plain colour login background in debyltech-cloud
+  become: true
+  become_user: "{{ podman_user }}"
+  ansible.builtin.shell: |
+    set -o pipefail
+    occ() { podman exec -u www-data debyltech-cloud php occ "$@"; }
+    if [ "$(occ config:app:get theming backgroundMime || true)" != backgroundColor ]; then
+      occ theming:config background backgroundColor >/dev/null
+      echo CHANGED
+    fi
+  args:
+    executable: /bin/bash
+  register: debyltech_background
+  changed_when: "'CHANGED' in debyltech_background.stdout"
+
 - name: check debyltech-cloud theming logos
   become: true
   become_user: "{{ podman_user }}"