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/routers/topics.py

@@ -30,7 +30,7 @@ async def list_topics(
 ) -> list[Topic]:
     response.headers["Cache-Control"] = "max-age=60, stale-while-revalidate=30"
     q = select(Topic).options(
-        noload(Topic.workstreams),
+        noload(Topic.workplans),
         noload(Topic.decisions),
         noload(Topic.progress_events),
     )