Implement room v12 (#943)

**Does not yet work!** Currently, state resolution does not correctly resolve conflicting states. Everything else appears to work as expected, so stateres will be fixed soon, then we should be clear for takeoff.

Also: a lot of things currently accept a nullable room ID that really just don't need to. This will need tidying up before merge. Some authentication checks have also been disabled temporarily but nothing important.

A lot of things are tagged with `TODO(hydra)`, those need resolving before merge. External contributors should PR to the `hydra/public` branch, *not* ` main`.

---

This PR should be squash merged.

Reviewed-on: https://forgejo.ellis.link/continuwuation/continuwuity/pulls/943
Co-authored-by: nexy7574 <git@nexy7574.co.uk>
Co-committed-by: nexy7574 <git@nexy7574.co.uk>

src/api/client/membership/knock.rs

@@ -373,7 +373,7 @@ async fn knock_room_helper_local(
 		.build_and_append_pdu(
 			PduBuilder::state(sender_user.to_string(), &content),
 			sender_user,
-			room_id,
+			Some(room_id),
 			&state_lock,
 		)
 		.await
@@ -502,6 +502,7 @@ async fn knock_room_helper_local(
 			knock_event,
 			once(parsed_knock_pdu.event_id.borrow()),
 			&state_lock,
+			room_id,
 		)
 		.await?;
 
@@ -672,7 +673,7 @@ async fn knock_room_helper_remote(
 	let statehash_after_knock = services
 		.rooms
 		.state
-		.append_to_state(&parsed_knock_pdu)
+		.append_to_state(&parsed_knock_pdu, room_id)
 		.await?;
 
 	info!("Updating membership locally to knock state with provided stripped state events");
@@ -701,6 +702,7 @@ async fn knock_room_helper_remote(
 			knock_event,
 			once(parsed_knock_pdu.event_id.borrow()),
 			&state_lock,
+			room_id,
 		)
 		.await?;