feat: add comprehensive OpenAPI 3.0 specification

- Created openapi.yaml (1,621 lines, 46KB)
- Documents all API endpoints with full schemas
- Authentication, Documents, Governance Services, Audit, Admin
- Added OpenAPI download link to api-reference.html
- Deployed to production

Task 12 (API Documentation) - OpenAPI spec complete

public/api-reference.html

@@ -72,6 +72,15 @@
               <strong>Base URL:</strong> <code class="bg-blue-100 px-2 py-1 rounded">http://localhost:9000/api</code>
             </p>
           </div>
+
+          <div class="mt-4 bg-green-50 border-l-4 border-green-500 p-4">
+            <p class="text-sm text-green-800">
+              <strong>📄 OpenAPI Specification:</strong> <a href="/docs/api/openapi.yaml" class="underline hover:text-green-900 font-semibold" download>Download OpenAPI 3.0 YAML</a>
+            </p>
+            <p class="text-xs text-green-700 mt-1">
+              Use this specification with Swagger UI, Postman, or any OpenAPI-compatible tool for interactive API exploration.
+            </p>
+          </div>
         </div>
 
         <!-- Authentication -->