fix: propagate Settings config changes to service managers and live pages

- PUT /api/config now calls service_manager.update_config() for each service
  so changes write to the service's own config file, not just cell_config.json
- email_manager.get_status() now reads smtp_port/imap_port/domain from its
  config file (defaults: 587/993/cell.local) and includes them in the response
- calendar_manager.get_status() includes configured port (default 5232)
- file_manager.get_status() uses configured port from service config
- Email.jsx reads imap_port/smtp_port from API status instead of hardcoding
- Settings service sections show "port changes require container restart" note

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

webui/src/pages/Settings.jsx

@@ -495,7 +495,8 @@ function Settings() {
         return (
           <Section key={key} icon={Icon} title={label} collapsible defaultOpen={false}>
             <Form data={data} onChange={(d) => updateServiceConfig(key, d)} />
-            <div className="flex justify-end mt-4">
+            <div className="flex items-center justify-between mt-4">
+              <span className="text-xs text-gray-400">Port/directory changes take effect after container restart.</span>
               <button
                 onClick={() => saveService(key)}
                 disabled={!dirty || saving}