feat(ecosystem): adopt hub-core dependency and CI pin gate (CORE-WP-0009)

Import slugify_or_default from hub-core, add contract tests, vendor hub-core in
Docker/Forgejo CI, document metadata isolation and pagination deferral, and
align INTENT/SCOPE with three-repo stack.

SCOPE.md

@@ -28,8 +28,19 @@ Core Hub replaces the Haskell/IHP Inter-Hub implementation with a contract-first
 - Rewriting unrelated consumers before the Core Hub compatibility contract exists
 - Retiring production Inter-Hub before migration and smoke evidence exists
 
+## Ecosystem position
+
+| Repo | Boundary |
+| --- | --- |
+| `hub-core` | Library — core-hub imports utils; framework models stay in `core_hub` |
+| `state-hub` | Dev coordination canonical owner for workplans/tasks until ADR says otherwise |
+| `core-hub` | This repo — `/api/v2`, framework tables, operator console |
+
+See `/home/worsch/the-custodian/docs/hub-ecosystem-architecture.md`.
+
 ## Non-Goals
 
 - Recreate IHP abstractions in Python
 - Bind the UI contract to React or any single frontend framework
 - Make State Hub disappear before Core Hub proves a compatible replacement path
+- Duplicating hub-core router factories or dev-hub workplan tables locally