Track active premium refactor stack

[daniele21]

Goal

Keep the canonical UX/UI workstream aligned with the actual premium-refactor execution state without modifying validated implementation branches.

Changes

• PVR-01/02/03 recorded as technically DONE inside the draft stack;
• PVR-04A/04B/05/06 recorded ACTIVE and linked to PVR-04A: refine decision surfaces #92/PVR-04B: refine run surfaces #93/PVR-05: refine evidence surfaces #94/PVR-06: refine secondary surfaces #95;
• documents the distinction between a technically complete slice and publication readiness while v0.5 goldens intentionally remain the before-baseline;
• records exact PVR-03 validation/PRE_REAL evidence and frozen shared ownership;
• updates integration strategy so PVR-07 reconciles page slices and PVR-08 is the first owner allowed to replace accepted pixel goldens.

Documentation-only coordination change. No product/runtime behavior changes.