Add Synology DSM support (#5315)

Adds optional support for running the playbook on Synology DSM 7+, detected
automatically via /etc/synoinfo.conf so that non-Synology hosts are unaffected.

Includes DSM-native user/group management (synouser/synogroup), a requests
version constraint for Docker SDK compatibility, and a boot-fix service that
re-shares the volume mount and starts matrix services skipped by DSM's boot
ordering. The shared-mount volume path is configurable via
matrix_base_synology_volume_path, and the make-shared step only runs when the
volume is not already shared.

Co-authored-by: CKSit <sitchiuki@gmail.com>
Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>
Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

roles/custom/matrix-base/tasks/setup_matrix_user.yml

@@ -1,31 +1,13 @@
 # SPDX-FileCopyrightText: 2020 - 2022 Slavi Pantaleev
 # SPDX-FileCopyrightText: 2022 Marko Weltzer
+# SPDX-FileCopyrightText: 2026 Chiu Ki Sit
 #
 # SPDX-License-Identifier: AGPL-3.0-or-later
 
 ---
 
-- name: Ensure Matrix group is created
-  ansible.builtin.group:
-    name: "{{ matrix_group_name }}"
-    gid: "{{ omit if matrix_user_gid is none else matrix_user_gid }}"
-    state: present
-    system: "{{ matrix_group_system }}"
-  register: matrix_group
+- ansible.builtin.include_tasks: "{{ role_path }}/tasks/setup_matrix_user_synology.yml"
+  when: matrix_base_host_is_synology
 
-- name: Ensure Matrix user is created
-  ansible.builtin.user:
-    name: "{{ matrix_user_name }}"
-    uid: "{{ omit if matrix_user_uid is none else matrix_user_uid }}"
-    state: present
-    group: "{{ matrix_group_name }}"
-    home: "{{ matrix_base_data_path }}"
-    create_home: false
-    system: "{{ matrix_user_system }}"
-    shell: "{{ matrix_user_shell }}"
-  register: matrix_user
-
-- name: Initialize matrix_user_uid and matrix_user_gid
-  ansible.builtin.set_fact:
-    matrix_user_uid: "{{ matrix_user.uid }}"
-    matrix_user_gid: "{{ matrix_group.gid }}"
+- ansible.builtin.include_tasks: "{{ role_path }}/tasks/setup_matrix_user_linux.yml"
+  when: not matrix_base_host_is_synology