feat: add SIEM integration templates

docs/reference/api.md

@@ -546,3 +546,16 @@ Receivers should verify these headers:
 Non-2xx responses are retried with exponential backoff until the endpoint's
 maximum attempt count is reached. Operators can inspect the delivery status,
 last response code, error text, and response excerpt without reading logs.
+
+## Integration Templates
+
+DMARQ ships operator-ready templates for normalized SIEM ingestion:
+
+| Endpoint | Purpose |
+| --- | --- |
+| `GET /api/v1/integrations/siem/templates` | Return versioned SIEM schemas, examples, config hints, and redaction guidance |
+
+The SIEM template bundle includes the stable `dmarq.siem.event.v1` envelope,
+examples for sender, compliance-drop, and alert events, and ingestion shapes for
+Splunk HEC, Elastic ECS, and Microsoft Sentinel custom logs. See
+[SIEM Integration Templates](siem-integrations.md) for the full operator guide.