hosting:clone no longer finds a source site in another project (15.33.0) #11247

[REQUIRED] Environment info

firebase-tools: 15.33.0 (works on 15.31.0)

Platform: macOS

[REQUIRED] Test case

Two Firebase projects:

• project-a, which owns hosting site site-a
• project-b, which owns hosting site site-b

We promote releases by cloning the live channel from one project's site to another's.

[REQUIRED] Steps to reproduce

firebase hosting:clone site-a:live site-b:live --project=project-b

[REQUIRED] Expected behavior

The live version of site-a is cloned to site-b:live, as in 15.31.0 and earlier. Site IDs are unique across all projects, so the CLI could find site-a without being told its project.

[REQUIRED] Actual behavior

GET https://firebasehosting.googleapis.com/v1beta1/projects/project-b/sites/site-a/channels/live 404
{"error":{"code":404,"message":"site `site-a` was not found on project `project-b`","status":"NOT_FOUND"}}

Error: Could not find the channel live for site site-a.

This seems to come from #11229, which replaced the - project wildcard with explicit project IDs. Now the source project defaults to --project. Writing the source as project-a:site-a:live works on 15.33.0, but 15.31.0 can't read that form. So a script can't support both versions, and existing cross-project hosting:clone scripts broke in a minor release.

Could you either:

1. look up the source site with the - wildcard when the source has no project, as before, or
2. mark this as a breaking change in the changelog and the hosting:clone help text, and have the error suggest the project:site:channel form when the site exists in another project?