7dcc910389
Document the MSP_MANAGED/CUSTOMER_MANAGED incident ownership mode across the
Claude/Internal/Architect/Testing/Customer tabs: the write matrix, the
/institution-keys/{key}/incident-mode endpoint + MSP toggle, controller-layer
assertWritable enforcement, IncidentDTO.institution, V90 migration, and the
known UI follow-up (customer nav still hidden).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>