Add render export adapter contract

docs/examples-index.md

@@ -37,6 +37,12 @@ This index maps example files to practical usecases and useful commands.
 | `examples/source-adapters/*.json`, `examples/source-adapters/normalized-output.md` | Expected envelopes for the v1 source adapter contract | Use as fixtures for `mkt source` commands after `MKTT-WP-0018` implementation |
 | `examples/source-adapters/fake-adapter-pyproject.toml` | External adapter entry point shape | Use as the fake package discovery fixture for source adapter contract tests |
 
+## Render Export Contract Fixtures
+
+| Files | Usecase | Try |
+| --- | --- | --- |
+| `examples/render/fake-render-request.yaml` | Deterministic render/export contract fixture | Use with the `render.fake` API adapter; no external renderer required |
+
 ## Cache, Backend, Policy, And Context
 
 | Files | Usecase | Try |