Evaluate native collaboration for popups and a premium review/approval workflow

[danieliser]

Part of #1341.

Hypothesis

Native WordPress collaboration features may cover contextual feedback on popup content, while Popup Maker Pro could add campaign-specific governance such as review states, approvers, notifications, and audit history.

Discovery scope

• Verify which Notes, suggestions, reactions, and collaboration APIs actually ship in the 7.1 RC.
• Determine whether native features can be enabled safely for the private popup post type.
• Test permissions, revisions, autosaves, concurrent editing, and iframe behavior.
• Determine whether feedback can attach to popup settings/preview regions or only block content.
• Avoid building a parallel comment system where native features suffice.
• Define the missing campaign-governance layer.
• Produce a Core / Pro / Hybrid / Defer decision.

Placement hypothesis to test

Core: compatibility and native collaboration enablement when broadly useful.
Pro: review states, assigned reviewers, change requests, approvals, notifications, enforcement, and audit history.

Sources

• WordPress 7.1 roadmap
• Collaborative editing outreach for 7.1