feat: vendor OpenAPI spec locally and update docs.json

Switch from remote raw.githubusercontent.com URL to a local openapi.yaml
so Mintlify always uses the spec committed in this repo. This fixes stale
docs that were missing the new analysis endpoints (impact, circular-dependencies,
test-coverage-map) because Mintlify was caching the remote URL.

The spec should be updated here whenever openapi-spec is updated.

Author: jonathanpopham

docs.json

@@ -38,7 +38,7 @@
       },
       {
         "tab": "API Reference",
-        "openapi": "https://raw.githubusercontent.com/supermodeltools/openapi-spec/main/openapi.yaml"
+        "openapi": "/openapi.yaml"
       }
     ]
   },