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_base.yml

@@ -7,11 +7,20 @@
 # SPDX-FileCopyrightText: 2022 Sebastian Gumprich
 # SPDX-FileCopyrightText: 2024 - 2025 Suguru Hirahara
 # SPDX-FileCopyrightText: 2024 László Várady
+# SPDX-FileCopyrightText: 2026 Chiu Ki Sit
 #
 # SPDX-License-Identifier: AGPL-3.0-or-later
 
 ---
 
+# Snapshot ownership before any changes so we can decide whether a recursive
+# chown is needed (only when uid/gid actually differs from expected).
+- name: Check current ownership of Matrix base path (Synology)
+  ansible.builtin.stat:
+    path: "{{ matrix_base_data_path }}"
+  register: matrix_base_data_path_stat
+  when: matrix_base_host_is_synology
+
 - name: Ensure Matrix base paths exists
   ansible.builtin.file:
     path: "{{ item }}"
@@ -28,3 +37,18 @@
     src: "{{ role_path }}/templates/bin/remove-all.j2"
     dest: "{{ matrix_bin_path }}/remove-all"
     mode: '0750'
+
+# On Synology, name-based chown works for directly-touched paths but leaves
+# existing sub-paths with stale numeric ownership when uid/gid changes between
+# runs. We recurse only when the pre-task uid/gid didn't match, so normal runs
+# skip the expensive tree walk entirely. chown -R is used instead of the file
+# module's recurse option to avoid Ansible iterating every entry in Python.
+- name: Ensure Matrix base path ownership is correct using numeric UID/GID (Synology)
+  ansible.builtin.command: chown -R {{ matrix_user_uid }}:{{ matrix_user_gid }} {{ matrix_base_data_path }}
+  changed_when: true
+  when: >-
+    matrix_base_host_is_synology and (
+      not matrix_base_data_path_stat.stat.exists or
+      matrix_base_data_path_stat.stat.uid | int != matrix_user_uid | int or
+      matrix_base_data_path_stat.stat.gid | int != matrix_user_gid | int
+    )