feat(cli): add open-reuse validate and register portfolio integrations

Implement Integration Definition validator CLI with schema and index checks,
pytest suite, and CI workflow. Register open-cmis-tck and issue-core-gitea in
the integration index.

Closes OPEN-WP-0003 and OPEN-WP-0004.

.claude/rules/stack-and-commands.md

@@ -1,7 +1,8 @@
 ## Stack
 
-- **Language:** Markdown-first registry and planning repo (no application runtime yet)
-- **Key deps:** State Hub ADR-001 workplans, `registry/indexes/capabilities.yaml`
+- **Language:** Python CLI + Markdown/YAML registry artifacts
+- **Key deps:** State Hub ADR-001 workplans, `jsonschema`, `pyyaml`,
+  `registry/indexes/integrations.yaml`
 
 ## Dev Commands
 
@@ -12,6 +13,12 @@ cat INTENT.md
 cat SCOPE.md
 ls workplans/
 
+# Install and validate
+python -m pip install -e ".[dev]"
+open-reuse validate
+open-reuse validate --repos-base /home/worsch
+pytest -q
+
 # After workplan or registry edits — from ~/state-hub
 make fix-consistency REPO=open-reuse