docs(sap): add Fisher UI Contract v1 + RJ addendum (ES/EN/PT)

[Cheewye]

Adds Fisher UI Contract v1 + RJ addendum docs for RJ (Maricá/Guanabara + Barra de São João) in ES/EN/PT.

What’s included

• New UI contract docs under docs/ui/** (v1 + badges + alerts thresholds + RJ addendum).
• Appendices order enforced: F → H → G (Sources of Truth + Data on Hold, RJ defaults/alerts thresholds, collision-free dock).
• Merge gate file: docs/ui/MERGE_GATE_E_F_H_EVIDENCE.md (require Appendix E + F + H for map/dock/forecast PRs).

Scope

• Docs only: docs/ui/** (no backend, no frontend/src changes).

Acceptance

• ✅ Appendix E + Appendix F + Appendix H present in ES/EN/PT RJ addendum files.