feat(c10y): add url_preview_check_root_domain

roles/custom/matrix-continuwuity/defaults/main.yml

@@ -202,6 +202,9 @@ matrix_continuwuity_config_url_preview_domain_contains_allowlist: []
 # Controls the `url_preview_domain_explicit_allowlist` setting.
 matrix_continuwuity_config_url_preview_domain_explicit_allowlist: []
 
+# Controls the `url_preview_check_root_domain` setting.
+matrix_continuwuity_config_url_preview_check_root_domain: false
+
 # Additional environment variables to pass to the container.
 #
 # Environment variables take priority over settings in the configuration file.

roles/custom/matrix-continuwuity/templates/continuwuity.toml.j2

@@ -1359,7 +1359,7 @@ url_preview_domain_explicit_allowlist = {{ matrix_continuwuity_config_url_previe
 # allowlist is still too broad for you but you still want to allow all the
 # subdomains under a root domain.
 #
-#url_preview_check_root_domain = false
+url_preview_check_root_domain = {{ matrix_continuwuity_config_url_preview_check_root_domain | to_json }}
 
 # List of forbidden room aliases and room IDs as strings of regex
 # patterns.