feat(ip): protect persona 'formula' — secret fields only super_admin sees/edits

IP protection so casual copying yields inferior results:
- SECRET_PERSONA_FIELDS (pains/objections/negotiation_levers/opener/tolerance +
  pain rootCause/resolutionConditions): only super_admin can view/edit them.
- list_personas/get_persona/update_persona/get_group strip these for role=admin (and
  hide sales_kit + pain-fit report from admins too).
- update_persona rejects admin attempts to set secret fields (403).
- PersonaForm hides the 'การขาย' recipe section for non-super-admin (shows locked note);
  auth.isSuperAdmin getter added.
Rebuilt dist. Added test_ip_protection.

frontend/dist/assets/GroupEdit-CFwXUOV9.css

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