Add note about redundant BusinessID in employee table

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

api/portal/addTeamMember.cfm

@@ -54,6 +54,9 @@ try {
   }
 
   // Insert new
+  // NOTE: BusinessID in lt_Users_Businesses_Employees is technically redundant since
+  // the business relationship is established via ServicePoint -> Beacon chain.
+  // Kept for legacy/convenience but could be derived from context.
   queryExecute("
     INSERT INTO lt_Users_Businesses_Employees (BusinessID, UserID, EmployeeStatusID, EmployeeIsActive)
     VALUES (?, ?, 2, 1)