Expose Synapse's `msc4306_enabled` experimental flag as a first-class MDAD
variable and wire it into `homeserver.yaml` alongside the other experimental
feature toggles.

This makes thread-subscriptions support explicit in playbook configuration,
rather than requiring operators to inject the upstream flag via raw
`matrix_synapse_configuration_extension_yaml`.

The variable intentionally controls only the Synapse feature flag. It does not
change the default `thread_subscriptions` worker count, which remains `0` in the
standard presets. Keeping those as separate choices avoids auto-starting an
experimental worker just because the upstream feature toggle is enabled.

Refs:
- b99a58719b/synapse/config/experimental.py (L600-L602)
- b99a58719b/synapse/rest/client/versions.py (L183-L184)

Add matrix_synapse_ext_password_provider_ldap_tls_options_ca_certs_file
variable to allow specifying a custom CA certificate file for LDAP TLS
verification. Useful when Synapse is running in a container that does not
trust a private/internal CA by default.

Example usage:
matrix_synapse_ext_password_provider_ldap_tls_options_ca_certs_file: /etc/ssl/certs/my-ca.crt

Ref:
- https://github.com/spantaleev/matrix-docker-ansible-deploy/pull/4882
- https://github.com/element-hq/synapse/pull/19204
- https://element-hq.github.io/synapse/latest/usage/configuration/config_documentation.html#enable_local_media_storage

We default it to `true`, keeping up with upstream and the old behavior.

s3-storage-provider users may set `matrix_synapse_enable_local_media_storage` to `false`
to disable local file caching.
This likely comes at the expense of some performance.

For matrix-media-repo users, it likely doesn't matter what this is set to,
as for a matrix-media-repo setup, all media-related API endpoints are
captured and forwarded to matrix-media-repo (before reaching Synapse).

* synapse - introduce matrix_synapse_url_preview_url_blacklist var

* Preserve original comments around `url_preview_url_blacklist`

---------

Co-authored-by: Aleksandrs Jansons <alex@peledu.casa>
Co-authored-by: Slavi Pantaleev <slavi@devture.com>

Related to https://github.com/element-hq/synapse/pull/18759

Currently problematic (leading to failures to start for Synapse) because of:
https://github.com/element-hq/synapse/pull/18759#issuecomment-3172744530

Related to https://github.com/spantaleev/matrix-docker-ansible-deploy/issues/4445

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

This works around an issue with Matrix Authentication Service's `syn2mas` sub-command (at version v0.16.0),
which chokes with an error:

> Error: Failed to load Synapse configuration
> Caused by:
> invalid type: found unit, expected struct EnableableSection for key "default.cas_config" in homeserver.yaml YAML file

This issue is likely to be fixed in MAS v0.16.1 or v0.17.0.

Ref:
- c4747dd177/docs/self-hosting.md (a-matrix-homeserver)
- e39fe3bc7f

* Add support for configuring Synapse's MSC4133 (Custom Profile Fields) experimental feature

* Reorder experimental_features in homeserver.yaml.j2 alphabetically

---------

Co-authored-by: Slavi Pantaleev <slavi@devture.com>

This is required by Element Call.

Ref:

- 93ae2aed98/docs/self-hosting.md (a-matrix-homeserver)
- https://github.com/spantaleev/matrix-docker-ansible-deploy/pull/3562

This is required by Element Call.

Ref:

- 93ae2aed98/docs/self-hosting.md (a-matrix-homeserver)
- https://github.com/spantaleev/matrix-docker-ansible-deploy/pull/3562

Fixes https://github.com/spantaleev/matrix-docker-ansible-deploy/issues/4113

It's useless and just makes the config longer.

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

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

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

* Replace "@user1" with "@alice"

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

* Replace "@user2" with "@bob"

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

---------

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

Related to 8a6b822bbd

Related to https://github.com/matrix-org/matrix-spec-proposals/pull/4108

Potential (unconfirmed) fix for https://github.com/spantaleev/matrix-docker-ansible-deploy/issues/3749

!qporfwt is used as an example of a room ID on https://spec.matrix.org/v1.12/#room-structure

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

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

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

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

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

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

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

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

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

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