fix(mgmt): regenerate api/openapi.json for 0.3.0

The OpenAPI 'info.version' tracks CARGO_PKG_VERSION; the 0.3.0 bump made the
checked-in spec stale (the openapi_document_is_complete_and_checked_in test).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

api/openapi.json

@@ -10,7 +10,7 @@
       "name": "MIT OR Apache-2.0",
       "identifier": "MIT OR Apache-2.0"
     },
-    "version": "0.0.1"
+    "version": "0.3.0"
   },
   "paths": {
     "/api/v1/clients": {