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.

registry/indexes/integrations.yaml

@@ -16,4 +16,34 @@ integrations:
       project_url: https://github.com/iamgio/quarkdown
     notes: >
       Reference integration for adapter reuse mode. Definition lives in the
-      consuming repository; this index row is the registry discovery surface.
+      consuming repository; this index row is the registry discovery surface.
+
+  - id: open-cmis-tck
+    name: Apache Chemistry OpenCMIS TCK Harness
+    status: registered
+    owner: open-cmis-tck
+    reuse_mode: adapter
+    risk_level: medium
+    path: integration/opencmis-tck.integration.yaml
+    repo: open-cmis-tck
+    upstream:
+      name: Apache Chemistry OpenCMIS TCK
+      project_url: https://github.com/apache/chemistry-opencmis
+    notes: >
+      Guide-board extension wrapping OpenCMIS TCK ConsoleRunner through a
+      cli-boundary adapter.
+
+  - id: issue-core-gitea
+    name: issue-core Gitea Backend
+    status: registered
+    owner: issue-core
+    reuse_mode: adapter
+    risk_level: medium
+    path: integration/gitea-backend.integration.yaml
+    repo: issue-core
+    upstream:
+      name: Gitea
+      project_url: https://github.com/go-gitea/gitea
+    notes: >
+      RemoteBackend adapter mapping issue-core task lifecycle onto the Gitea
+      issues API.