feat(documenso): v2 coverage on getDocument/health + reminder webhook + admin UI benefits panel

- documenso-client.ts: getDocument now routes to /api/v2/envelope/{id} when port apiVersion=v2; checkDocumensoHealth surfaces resolved apiVersion for the admin Test button
- webhook route: handle DOCUMENT_REMINDER_SENT (structured log only, no audit-table noise) + DOCUMENT_CREATED / DOCUMENT_SENT (informational log)
- Admin Documenso page: prominent v1-vs-v2 explainer card listing v2-only capabilities the CRM already exploits (bulk fields, percent coords, richer fieldMeta, v2 webhook aliases, envelope endpoints) + amber roadmap callout for sequential signing / redirectUrl / template/use / envelope/update / non-SIGNER roles
- CLAUDE.md: idempotency + v2 webhook event list, berth-rules engine section, DOCUMENSO_API_URL gotcha, storage backend listByPrefix + timeout

Still v1-only (call out in admin UI roadmap): createDocument, generateDocumentFromTemplate, sendDocument, sendReminder, downloadSignedPdf. Migrating template/use to v2 requires per-template field-ID mapping in template config; deferred to a follow-up plan.

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

src/lib/services/documenso-client.ts

@@ -229,7 +229,12 @@ export async function sendDocument(docId: string, portId?: string): Promise<Docu
 }
 
 export async function getDocument(docId: string, portId?: string): Promise<DocumensoDocument> {
-  return documensoFetch(`/api/v1/documents/${docId}`, undefined, portId).then(normalizeDocument);
+  const { apiVersion } = await resolveCreds(portId);
+  // v1: GET /api/v1/documents/{id}
+  // v2: GET /api/v2/envelope/{id} — same response normalizer (id ↔ documentId,
+  //      recipientId ↔ id handled by normalizeDocument).
+  const path = apiVersion === 'v2' ? `/api/v2/envelope/${docId}` : `/api/v1/documents/${docId}`;
+  return documensoFetch(path, undefined, portId).then(normalizeDocument);
 }
 
 /**
@@ -295,13 +300,16 @@ export async function downloadSignedPdf(docId: string, portId?: string): Promise
 /** Convenience health-check used by the admin "Test connection" button. */
 export async function checkDocumensoHealth(
   portId?: string,
-): Promise<{ ok: boolean; status?: number; error?: string }> {
+): Promise<{ ok: boolean; status?: number; error?: string; apiVersion?: DocumensoApiVersion }> {
   try {
-    const { baseUrl, apiKey } = await resolveCreds(portId);
+    const { baseUrl, apiKey, apiVersion } = await resolveCreds(portId);
+    // Both v1 and v2 expose /api/v1/health (v2 keeps the v1 path for
+    // backward compat). If a v2 deployment ever moves this we'll add a
+    // v2 branch — but as of Documenso 2.x there isn't a v2 health path.
     const res = await fetchWithTimeout(`${baseUrl}/api/v1/health`, {
       headers: { Authorization: `Bearer ${apiKey}` },
     });
-    return { ok: res.ok, status: res.status };
+    return { ok: res.ok, status: res.status, apiVersion };
   } catch (err) {
     return { ok: false, error: err instanceof Error ? err.message : 'Unknown error' };
   }