Rayfin CLI cannot discover Fabric trial workspace

Context

Split from https://github.com/microsoft/rayfin/issues/24 (sub-issue 4 of 4).

Problem

After scaffolding, the Rayfin CLI does not list or detect a newly created Fabric trial workspace. This blocks completing the end-to-end setup for new users.

Steps to Reproduce

1. Create a Fabric trial workspace
2. Scaffold a Rayfin app
3. Run the CLI workspace discovery flow
4. The trial workspace is not listed

Expected Behavior

The CLI should discover and list all Fabric workspaces the user has access to, including trial workspaces.

Investigation Notes

Possible causes:

• Trial workspaces may use a different API or have different visibility in the Fabric workspace listing API
• The CLI may be filtering workspace types and excluding trial workspaces
• Permission/scope issues with the CLI's auth token for trial tenants

Suggested Fix

• Check the workspace listing API call and verify trial workspaces are included in the response
• Ensure the CLI doesn't filter out trial workspace types
• Add a note in docs if trial workspaces require additional setup steps