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/account.rs

@@ -500,7 +500,7 @@ pub(crate) async fn register_route(
 				.await
 				.is_ok_and(is_equal_to!(1))
 			{
-				services.admin.make_user_admin(&user_id).await?;
+				services.admin.make_user_admin(&user_id).boxed().await?;
 				warn!("Granting {user_id} admin privileges as the first user");
 			} else if services.config.suspend_on_register {
 				// This is not an admin, suspend them.
@@ -924,7 +924,7 @@ pub async fn full_user_deactivate(
 				.build_and_append_pdu(
 					PduBuilder::state(String::new(), &power_levels_content),
 					user_id,
-					room_id,
+					Some(room_id),
 					&state_lock,
 				)
 				.await