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/models/managed_repo.py

@@ -1,8 +1,8 @@
 import uuid
-from datetime import datetime
+from datetime import date, datetime
 
-from sqlalchemy import DateTime, ForeignKey, String, Text
-from sqlalchemy.dialects.postgresql import JSONB, UUID
+from sqlalchemy import Date, DateTime, ForeignKey, String, Text
+from sqlalchemy.dialects.postgresql import ARRAY, JSONB, UUID
 from sqlalchemy.orm import Mapped, mapped_column, relationship
 
 from api.models.base import Base, TimestampMixin, new_uuid
@@ -36,6 +36,15 @@ class ManagedRepo(Base, TimestampMixin):
         DateTime(timezone=True), nullable=True
     )
 
+    category: Mapped[str | None] = mapped_column(String(50), nullable=True)
+    secondary_domains: Mapped[list[str] | None] = mapped_column(ARRAY(Text), nullable=True)
+    capability_tags: Mapped[list[str] | None] = mapped_column(ARRAY(Text), nullable=True)
+    business_stake: Mapped[list[str] | None] = mapped_column(ARRAY(Text), nullable=True)
+    business_mechanics: Mapped[list[str] | None] = mapped_column(ARRAY(Text), nullable=True)
+    classified_at: Mapped[date | None] = mapped_column(Date, nullable=True)
+    classified_by: Mapped[str | None] = mapped_column(String(50), nullable=True)
+    standard_version: Mapped[str | None] = mapped_column(String(20), nullable=True)
+
     domain: Mapped["Domain"] = relationship(  # noqa: F821
         "Domain", back_populates="repos", lazy="selectin"
     )