Add a new workspace member or update an existing member’s permissions
admin - Full workspace access, can manage members and settingssend - Can view, edit, and send emailsedit - Can view and edit drafts, but cannot sendview - Read-only access to threads and emailsINSERT ... ON CONFLICT DO UPDATE pattern - if the member already exists, their permission is updatedADMIN_EMAILS) are automatically set to admin permission, overriding the requested permissionsrc/app/api/members/route.ts:55