MAS now connects to the playbook-managed Postgres via a UNIX socket by
default (when available), matching the approach already used by Synapse.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

syn2mas reads Synapse's homeserver.yaml and reuses the database
connection details from there.

When Synapse is configured to reach the integrated Postgres over a UNIX socket,
the temporary syn2mas container was given the config file but not the socket mount,
so migrations could fail even though Synapse itself was configured correctly.

Wire the Synapse socket settings into MAS via playbook vars and mount
the same socket path into the syn2mas container, so migrations work in
socket-based deployments without coupling the MAS role directly to
Synapse role variables.

Add change-tracking and restart_necessary computation for:
- matrix-authentication-service (custom role in this repo)
- container-socket-proxy, traefik-certs-dumper, postgres, exim-relay,
  cinny, livekit-server (external roles, bumped in requirements.yml)

Wire all 7 services in group_vars to use their _restart_necessary variable
instead of hardcoded true.

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

Ref:

- https://github.com/spantaleev/matrix-docker-ansible-deploy/pull/4647
- https://github.com/element-hq/matrix-authentication-service/releases/tag/v1.4.0
- https://github.com/element-hq/matrix-authentication-service/pull/5109

Regression since db54063a0c

Fixes https://github.com/spantaleev/matrix-docker-ansible-deploy/issues/4617

Builds up on top of d0adc8a374

Fixes https://github.com/spantaleev/matrix-docker-ansible-deploy/issues/4297

Supersedes https://github.com/spantaleev/matrix-docker-ansible-deploy/pull/4300

Signed-off-by: Suguru Hirahara <acioustick@noreply.codeberg.org>

This:

- brings consistency - no more mixing `_name_prefix` and `_registry_prefix`
- adds extensibility - a future patch will allow reconfiguring all registry prefixes for all roles in the playbook

We still have `_docker_` vs `_container_` inconsistencies.
These may be worked on later.

- Fix punctuations
- Set the common expression for matrix_authentication_service_config_email_mode

Signed-off-by: Suguru Hirahara <acioustick@noreply.codeberg.org>

This makes it possible to migrate from Synapse when OIDC had been used
and the Synapse user database contains OIDC-sourced users.

Fixes https://github.com/spantaleev/matrix-docker-ansible-deploy/issues/3108

Related to https://github.com/spantaleev/matrix-docker-ansible-deploy/pull/3562