Switch to (intermeddiate) call view with media settings instead of a modal dialog on starting/joining a call

How to use GitHub

• Please use the 👍 reaction to show that you are interested into the same feature.
• Please don't comment if you have no relevant information to add. It's just extra noise for everyone subscribed to this issue.
• Subscribe to receive notifications on status change and new comments.

Feature request

Is your feature request related to a problem? Please describe.

• Starting a call requires 2 actions: Start/Join + Confirm, on the media settings dialog
• The dialog is modal, blocking the user flow. For example, from reading the chat
• In general looks very chat-first, with less call-experience
• Also good for lobby/guests

Describe the solution you'd like

• Starting/Joining a call immediately switches to the call view (without actually staring/joining any call)
  • Navigation is collapsed
  • Chat is moved to the sidebar
  • Everything looks like "Waiting for others to join a call", but with the media settings instead
• During the call, media settings are integrated into the controls
  • See also: https://github.com/nextcloud/spreed/issues/15025
• Media settings dialog still exists as the current dialog for Talk Settings and Dashboard

Very quickly created draft:

The issue names no files, tests, or entry points; start by reviewing the proposed call-view flow and related issue #15025. Before implementation, define the affected start/join, lobby, sidebar, and in-call media-settings paths; done requires an agreed design covering those flows.