Support matching room_id as publicrooms search term.

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

tuwunel-example.toml

@@ -473,6 +473,22 @@
 #
 #allow_public_room_directory_without_auth = false
 
+# Allows room directory searches to match on partial room_id's when the
+# search term starts with '!'.
+#
+#allow_public_room_search_by_id = true
+
+# Set this to false to limit results of rooms when searching by ID to
+# those that would be found by an alias or other query; specifically
+# those listed in the public rooms directory. By default this is set to
+# true allowing any joinable room to match. This satisfies the Principle
+# of Least Expectation when pasting a room_id into a search box with
+# intent to join; many rooms simply opt-out of public listings. Therefor
+# to prevent this feature from abuse, knowledge of several characters of
+# the room_id is required before any results are returned.
+#
+#allow_unlisted_room_search_by_id = true
+
 # Allow guests/unauthenticated users to access TURN credentials.
 #
 # This is the equivalent of Synapse's `turn_allow_guests` config option.