feat(uat-p5): activity-feed module, signing-order tri-state, webhook health card

- Activity-feed: shared formatting module
  (src/components/shared/activity-formatting.ts) centralises action
  verbs, badge variants, entity-type labels, enum-value normalisation,
  shortValue, and buildDiffLine. The dashboard widget feed and the
  per-entity audit feed now both consume it - duplicate ~250 lines
  collapsed, vocabularies aligned, badge palette unified.
- Signing order setting becomes tri-state. The new
  TEMPLATE_DEFAULT value (the new default) skips overriding the
  template's own signingOrder so each Documenso template's stored
  setting wins. PARALLEL / SEQUENTIAL keep forcing the override.
- Admin Documenso page now ships a Webhook health card backed by
  /api/v1/admin/documenso-webhook/health (secret status,
  expected URL, last received event, recent secret rejections) and
  a "Test now" button that fires a synthetic DOCUMENT_OPENED through
  /api/v1/admin/documenso-webhook/test against the local receiver
  to verify the full pipeline without driving a real Documenso event.

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

src/app/(dashboard)/[portSlug]/admin/documenso/page.tsx

@@ -4,6 +4,7 @@ import { RegistryDrivenForm } from '@/components/admin/shared/registry-driven-fo
 import { DocumensoTestButton } from '@/components/admin/documenso/documenso-test-button';
 import { EmbeddedSigningCard } from '@/components/admin/documenso/embedded-signing-card';
 import { TemplateSyncButton } from '@/components/admin/documenso/template-sync-button';
+import { WebhookHealthCard } from '@/components/admin/documenso/webhook-health-card';
 import { PageHeader } from '@/components/shared/page-header';
 import { Card, CardContent, CardHeader, CardTitle } from '@/components/ui/card';
 
@@ -205,6 +206,8 @@ export default function DocumensoSettingsPage() {
       />
 
       <EmbeddedSigningCard />
+
+      <WebhookHealthCard />
     </div>
   );
 }