Enable permalink jitsi url per room

Description:

When starting a jitsi video call in the same room, two different calls from two different members give two different rooms (two different URLs).

I would like to be able to create a permalink so that I can share this invite link permanently to someone outside rocketchat: something like https://short.link/myVideoCall.
Then I'd like to be able to join the video call directly from rocketchat anytime I want. (In rocketchat, a video call seems to expire after a while, you cannot join it anymore).

But I cannot do that since the rocketchat jitsi video call URL is constantly changing, after each new call.

I understand that some people want the very opposite (see #24839). Maybe it might be a setting when configuring jitsi, the idea is to allow permalink so that people from the outside could join the call from a permalink, instead of a generated link.

Rocketchat server: 5.4.0

Start by reviewing Rocket.Chat's existing Jitsi video-call integration and issue #24839 to understand the opposing permalink behavior. Define where a per-room permanent URL would be configured and how it should remain joinable after calls expire; completion requires an agreed design and implementation scope.