Easy!Appointments is a self hosted appointment scheduler. Versions prior to 1.6.0 correctly filter provider-scoped appointments in the `appointments/search` response, proving that provider isolation …

Summary

Easy!Appointments is a self hosted appointment scheduler. Versions prior to 1.6.0 correctly filter provider-scoped appointments in the `appointments/search` response, proving that provider isolation is an intended security boundary. However, the direct mutation endpoints `appointments/store` and `appointments/update` only check generic appointment privileges and never verify that the submitted `id_users_provider` belongs to the current session. A normal authenticated provider can inject new app…