Initial schemas and validation with extension workplan

docs/markitect-main-scope-assessment.md

@@ -47,6 +47,17 @@ consumer needs them through the new library contract:
 4. Treat old code as reference material; do not preserve backward compatibility unless the new contract explicitly needs it.
 5. Keep database, platform, and domain lifecycle concerns out of this repo.
 
+## Practicality Reassessment
+
+The first implementation slices intentionally rebuilt the clean parser and JSON
+Schema spine. That is necessary but not sufficient. The legacy project already
+showed that heading counts and raw structural schemas have limited practical
+utility.
+
+The successor should prioritize a document contract framework before going much
+deeper into generic tooling. See `docs/practical-schema-framework-research.md`
+and `workplans/MKTT-WP-0004-practical-contract-framework.md`.
+
 ## Initial Architecture Target
 
 ```text