Add Quarkdown render adapter boundary

examples/quarkdown-render-request.yaml

@@ -0,0 +1,17 @@
+schema_version: markitect.render.export.v1
+operation: render-artifact
+profile: pdf
+source_path: docs/demo.md
+source: |
+  # Demo
+
+  This is a Markitect-compatible source document handed to Quarkdown.
+options:
+  artifact_stem: demo
+  output_dir: quarkdown-output
+  permissions:
+    - project-read
+  deny_network: true
+metadata:
+  adapter: render.quarkdown
+  real_runtime_required: true