Add conditional restart support to client, bot, and bridge roles

For each of the 34 roles (3 clients, 9 bots, 22 bridges), this commit:
- Adds `_restart_necessary: false` default variable
- Adds `register:` directives to config/image/systemd tasks
- Computes `_restart_necessary` via set_fact (OR of all .changed results)
- Wires `(_restart_necessary | bool)` in group_vars/matrix_servers

This allows the systemd service manager to skip unnecessary restarts
when running install-* tags and nothing actually changed.

Service roles and complex multi-service roles will follow separately.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

roles/custom/matrix-bot-maubot/defaults/main.yml

@@ -180,3 +180,13 @@ matrix_bot_maubot_systemd_required_services_list_custom: []
 
 # List of systemd services that matrix-bot-maubot.service wants
 matrix_bot_maubot_systemd_wanted_services_list: []
+
+# matrix_bot_maubot_restart_necessary controls whether the service
+# will be restarted (when true) or merely started (when false) by the
+# systemd service manager role (when conditional restart is enabled).
+#
+# This value is automatically computed during installation based on whether
+# any configuration files, the systemd service file, or the container image changed.
+# The default of `false` means "no restart needed" — appropriate when the role's
+# installation tasks haven't run (e.g., due to --tags skipping them).
+matrix_bot_maubot_restart_necessary: false

roles/custom/matrix-bot-maubot/tasks/setup_install.yml

@@ -34,6 +34,7 @@
     owner: "{{ matrix_user_name }}"
     group: "{{ matrix_group_name }}"
     mode: "u=rwx"
+  register: matrix_bot_maubot_config_result
 
 - name: Ensure maubot image is pulled
   community.docker.docker_image:
@@ -42,10 +43,10 @@
     force_source: "{{ matrix_bot_maubot_docker_image_force_pull if ansible_version.major > 2 or ansible_version.minor >= 8 else omit }}"
     force: "{{ omit if ansible_version.major > 2 or ansible_version.minor >= 8 else matrix_bot_maubot_docker_image_force_pull }}"
   when: "not matrix_bot_maubot_container_image_self_build|bool"
-  register: result
+  register: matrix_bot_maubot_container_image_pull_result
   retries: "{{ devture_playbook_help_container_retries_count }}"
   delay: "{{ devture_playbook_help_container_retries_delay }}"
-  until: result is not failed
+  until: matrix_bot_maubot_container_image_pull_result is not failed
 
 - when: matrix_bot_maubot_container_image_self_build | bool
   block:
@@ -100,6 +101,7 @@
     group: "{{ matrix_group_name }}"
   with_items:
     - labels
+  register: matrix_bot_maubot_support_files_result
 
 - name: Ensure maubot container network is created
   community.general.docker_network:
@@ -113,3 +115,14 @@
     src: "{{ role_path }}/templates/systemd/matrix-bot-maubot.service.j2"
     dest: "{{ devture_systemd_docker_base_systemd_path }}/matrix-bot-maubot.service"
     mode: 0644
+  register: matrix_bot_maubot_systemd_service_result
+
+- name: Determine whether maubot needs a restart
+  ansible.builtin.set_fact:
+    matrix_bot_maubot_restart_necessary: >-
+      {{
+        matrix_bot_maubot_config_result.changed | default(false)
+        or matrix_bot_maubot_support_files_result.changed | default(false)
+        or matrix_bot_maubot_systemd_service_result.changed | default(false)
+        or matrix_bot_maubot_container_image_pull_result.changed | default(false)
+      }}