matrix-tuwunel: add Tuwunel homeserver role (#5200)

Tuwunel is a Matrix homeserver maintained by the matrix-construct
organisation. See https://matrix-construct.github.io/tuwunel/.

The rendered TOML emits only keys exposed as Ansible variables; the
rest fall back to tuwunel's upstream defaults. Anything not surfaced
can be set via the TUWUNEL_* env extension or by overriding the
template path.

Popular features Tuwunel adds variables for:

- OAuth2/OIDC identity providers (a list of `[[global.identity_provider]]`
  blocks; brand-aware defaults for Google, GitHub, Keycloak, MAS, etc)
- LDAP and JWT authentication
- Media storage providers (native local and S3 with multipart upload)
- RocksDB tuning (compression, direct_io, parallelism, online backups)
- Native TLS dual-protocol mode
- Blurhashing, Sentry crash reporting

Auto-wired from existing playbook globals: well-known client URL,
TURN/coturn, MatrixRTC LiveKit URL, federation.

The `tuwunel-migrate-from-conduwuit` tag performs a binary-swap
migration. Migration from any other Conduit derivative is unsupported
and would corrupt the database.

Signed-off-by: Jason Volk <jason@zemos.net>

roles/custom/matrix-tuwunel/tasks/uninstall.yml

@@ -0,0 +1,24 @@
+# SPDX-FileCopyrightText: 2026 MDAD project contributors
+# SPDX-FileCopyrightText: 2026 Slavi Pantaleev
+#
+# SPDX-License-Identifier: AGPL-3.0-or-later
+
+---
+
+- name: Check existence of matrix-tuwunel service
+  ansible.builtin.stat:
+    path: "{{ devture_systemd_docker_base_systemd_path }}/matrix-tuwunel.service"
+  register: matrix_tuwunel_service_stat
+
+- when: matrix_tuwunel_service_stat.stat.exists | bool
+  block:
+    - name: Ensure matrix-tuwunel is stopped
+      ansible.builtin.systemd:
+        name: matrix-tuwunel
+        state: stopped
+        daemon_reload: true
+
+    - name: Ensure matrix-tuwunel.service doesn't exist
+      ansible.builtin.file:
+        path: "{{ devture_systemd_docker_base_systemd_path }}/matrix-tuwunel.service"
+        state: absent