refactor(settings/audit): conditional retention disclosure + flat layout

Drops the wrapping details-card so the audit toggle and retention input
read like the email page. The audit switch now uses role="switch" and a
new app-settings-audit component (built on the existing
createConditionalToggleInit primitive) hides the retention block when
audit is disabled — the input is meaningless without audit on, and the
control state syncs automatically on toggle. The redundant info
blockquote and the toggle's paraphrased DB description are gone.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

web/js/app-init.js

@@ -20,6 +20,7 @@ import { initCustomFieldOptionsToggle } from './components/app-custom-field-opti
 import { initTenantSsoToggle } from './components/app-tenant-sso-toggle.js';
 import { initTenantLdapToggle } from './components/app-tenant-ldap-toggle.js';
 import { initTelemetrySettings } from './components/app-settings-telemetry.js';
+import { initSettingsAudit } from './components/app-settings-audit.js';
 import { initStandardDetailPages } from './components/app-standard-detail-page.js';
 import { initAutoSubmit } from './components/app-auto-submit.js';
 import { initTabs } from './components/app-tabs.js';
@@ -196,6 +197,10 @@ const bootRuntime = async () => {
     scope: 'global',
     configPath: 'components.settingsTelemetry',
   });
+  runtime.register('settings-audit', initSettingsAudit, {
+    scope: 'global',
+    configPath: 'components.settingsAudit',
+  });
   runtime.register('auto-submit', initAutoSubmit, {
     scope: 'global',
     configPath: 'components.autoSubmit',

web/js/components/app-settings-audit.js

@@ -0,0 +1,24 @@
+/**
+ * Shows/hides audit retention field based on the audit-enabled toggle.
+ */
+import { syncControlState, createConditionalToggleInit } from '../core/app-conditional-controls.js';
+
+const initRoot = (root) => {
+  const enabledInput = root.querySelector('[data-audit-enabled-toggle]');
+  const dependent = root.querySelector('[data-audit-when-enabled]');
+  if (!(enabledInput instanceof HTMLInputElement) || !(dependent instanceof HTMLElement)) {
+    return null;
+  }
+  const sync = () => syncControlState(dependent, enabledInput.checked);
+  enabledInput.addEventListener('change', sync);
+  sync();
+  return () => {
+    enabledInput.removeEventListener('change', sync);
+  };
+};
+
+export const initSettingsAudit = createConditionalToggleInit({
+  rootSelector: '[data-settings-audit-root]',
+  boundKey: 'settingsAuditBound',
+  initRoot,
+});