feat: connect UsersPage and SettingsPage SMTP to API + extend user roles/fields

- Migration 034: extend users table with phone, position, active columns; add new roles (receptionist, accountant, security)
- Backend users.ts: accept phone/position on create, accept phone/position/active/role on update; managers can now assign all non-admin roles
- types/index.ts + api.ts: add phone, position, active to User type and users create/update payload types
- UsersPage: fix mapRole to handle all 5 roles, fix toStaffUser to use real phone/position/active from API, fix handleSave to pass all fields
- SettingsPage: load SMTP settings from hotelSettings API on mount, save SMTP on handleSave when section === 'notify'

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/migrations/034_users_extend.sql

@@ -0,0 +1,9 @@
+-- Extend role constraint to support more roles
+ALTER TABLE users DROP CONSTRAINT IF EXISTS users_role_check;
+ALTER TABLE users ADD CONSTRAINT users_role_check
+  CHECK (role IN ('manager', 'housekeeper', 'super_admin', 'receptionist', 'accountant', 'security'));
+
+-- Add new columns
+ALTER TABLE users ADD COLUMN IF NOT EXISTS phone VARCHAR(50);
+ALTER TABLE users ADD COLUMN IF NOT EXISTS position VARCHAR(100);
+ALTER TABLE users ADD COLUMN IF NOT EXISTS active BOOLEAN NOT NULL DEFAULT true;