Add / edit a PERSONAL integration connection for the current user.
:new shows a provider picker (only for_scope(:personal) providers), then a
name + setup-fields form. :edit loads the connection owner-scoped and shows
its setup fields with Test / Delete.
Every context call is scoped to owner: {:user, uuid} where the uuid comes
ONLY from the request scope — a crafted :edit uuid for another user's row
fails closed (redirects), never exposing their credentials. No OAuth flow:
personal providers are self-owned-secret types validated in place.
Renders with the shared Components.Core.IntegrationsUI so it stays visually
consistent with the website-wide page (Live.Settings.IntegrationForm).