Overhaul Workflow Reports and Pages

[guerler]

The current setup for Workflow Reports and Pages has usability issues:

1. Reports are read-only unless you own the workflow.
2. To edit a report, it must be copied to a page, but then it can’t be reused in the workflow.
3. Reports and pages are similar under the hood (reports use labels populated after workflow runs, pages assign datasets directly), but they work very differently for users.

Proposed Changes

1. Modernize the UI for reports and pages.
2. Allow conversion between reports and pages.
3. Make reports editable without requiring workflow ownership and keep them reusable in workflows.

Goal

Improve flexibility, usability, and integration of reports and pages while simplifying the user experience.