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.

.repo-classification.yaml

@@ -7,12 +7,10 @@ repo_classification:
   domain: infotech
   secondary_domains: []
   capability_tags:
-  - interaction-framework
-  - state-coordination
-  - agent-coordination
   - platform
-  - api
-  - registry
+  - orchestration
+  - coordination
+  - control
   business_stake:
   - technology
   - execution
@@ -20,4 +18,7 @@ repo_classification:
   - operation
   - coordination
   - control
-  notes: Third-generation production interaction framework replacing Inter-Hub goals on the natural Coulomb stack.
+  notes: >-
+    Production framework layer in the hub-core, state-hub, and core-hub stack
+    (CUST-WP-0057). Depends on hub-core for shared utils; owns /api/v2 and
+    framework tables.