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/extension_point.py

@@ -1,7 +1,7 @@
 import uuid
 from datetime import datetime
 
-from pydantic import BaseModel, ConfigDict
+from pydantic import AliasChoices, BaseModel, ConfigDict, Field
 
 from api.models.extension_point import EPStatus
 
@@ -18,7 +18,10 @@ class EPCreate(BaseModel):
     status: EPStatus = EPStatus.open
     priority: str = "medium"
     topic_id: uuid.UUID | None = None
-    workstream_id: uuid.UUID | None = None
+    workplan_id: uuid.UUID | None = Field(
+        default=None,
+        validation_alias=AliasChoices("workplan_id", "workstream_id"),
+    )
 
 
 class EPUpdate(BaseModel):
@@ -29,7 +32,10 @@ class EPUpdate(BaseModel):
     ep_type: str | None = None
     status: EPStatus | None = None
     priority: str | None = None
-    workstream_id: uuid.UUID | None = None
+    workplan_id: uuid.UUID | None = Field(
+        default=None,
+        validation_alias=AliasChoices("workplan_id", "workstream_id"),
+    )
 
 
 class EPRead(BaseModel):
@@ -45,6 +51,10 @@ class EPRead(BaseModel):
     status: EPStatus
     priority: str
     topic_id: uuid.UUID | None = None
-    workstream_id: uuid.UUID | None = None
+    workplan_id: uuid.UUID | None = None
     created_at: datetime
+
+    @property
+    def workstream_id(self) -> uuid.UUID | None:
+        return self.workplan_id
     updated_at: datetime