feat(classification-spine): implement STATE-WP-0065 repo-anchored model

Replace the ad-hoc coordination-domain spine with the Repo Classification
Standard: 14 market domains, classification columns on managed_repos, and
workplans anchored by repo_id (topic_id optional).

- Add Alembic migration d8e9f0a1b2c3 with data backfill and workstream→workplan rename
- Add api/classification.py validation and register-from-classification tooling
- Expose workplan-first REST/MCP surface with legacy workstream aliases
- Add C-24 consistency rule and legacy domain frontmatter mapping
- Update dashboard repos page with category/capability/stake filters
- Update orientation docs; mark STATE-WP-0065 finished

api/schemas/__init__.py

@@ -1,4 +1,5 @@
 from api.schemas.topic import TopicCreate, TopicUpdate, TopicRead, TopicWithWorkstreams
+from api.schemas.workplan import WorkplanCreate, WorkplanUpdate, WorkplanRead
 from api.schemas.workstream import WorkstreamCreate, WorkstreamUpdate, WorkstreamRead
 from api.schemas.task import TaskCreate, TaskUpdate, TaskRead
 from api.schemas.decision import DecisionCreate, DecisionUpdate, DecisionRead
@@ -9,6 +10,7 @@ from api.schemas.technical_debt import TDCreate, TDUpdate, TDRead
 
 __all__ = [
     "TopicCreate", "TopicUpdate", "TopicRead", "TopicWithWorkstreams",
+    "WorkplanCreate", "WorkplanUpdate", "WorkplanRead",
     "WorkstreamCreate", "WorkstreamUpdate", "WorkstreamRead",
     "TaskCreate", "TaskUpdate", "TaskRead",
     "DecisionCreate", "DecisionUpdate", "DecisionRead",