D25: dashboard tabs and world overlays; premultiplied-alpha flag. D26: one world overlay for all notifications. D27: MVP placement "spawn in front, then stay". D28: DSH-1 (web UI out-of-the-box test) joins the MVP, full dashboard becomes DSH-2. Add the research on notification UI in VR (DESIGN.md, Appendix A). Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>