fix: remove canWrite from IAM — it is IAM RBAC, not our app logic

- IAM permissions.can_write defaults to false for all users
- Our app controls writes via adminMode + company membership

ui/index.js

@@ -64,7 +64,6 @@ function createUiRouter({ auth, MOCK_USERS, authLimiter }) {
       const canAdminMode = !!(iamAdmin && activeClientId === ADMIN_CLIENT_ID)
         || (isNail && activeClientId === ADMIN_CLIENT_ID);
       const sessionIsImpersonated = req.session && req.session.user && req.session.user.isImpersonated;
-      const sessionCanWrite = req.session && req.session.user ? req.session.user.canWrite : true;
       req.user = {
         clientId:       rawClientId,
         allClientIds,
@@ -73,7 +72,6 @@ function createUiRouter({ auth, MOCK_USERS, authLimiter }) {
         companyName:    payload.company_name  || payload.companyName || activeClientId,
         email:          req.session?.user?.email || payload.email || payload.login || activeClientId + '@unknown',
         isAdmin:        iamAdmin || isNail,
-        canWrite:       sessionCanWrite,
         isImpersonated: !!sessionIsImpersonated,
         originalUserEmail:    req.session?.user?.originalUserEmail || '',
         originalUserFullName: req.session?.user?.originalUserFullName || '',