feat(goals): add domain/repo goal tracking and update_workstream MCP tool

- Migration c5d6e7f8a9b0: domain_goals and repo_goals tables, repo_goal_id FK on workstreams
- DomainGoal: one active per domain (partial unique index), status active/archived/superseded
- RepoGoal: integer priority, status active/paused/completed/archived, optional domain_goal_id link
- WorkstreamUpdate schema and router extended with repo_goal_id and repo_goal_id filter
- 6 new MCP goal tools: create_domain_goal, get_domain_goals, activate_domain_goal, create_repo_goal, get_repo_goals, update_repo_goal
- update_workstream MCP tool: patch any subset of workstream fields (title, description, owner, due_date, repo_goal_id, status)
- get_domain_summary extended with goal_guidance (needs_workplan, alignment_warnings) signals
- Dashboard goals.md page and docs/goals.md reference page
- CLAUDE.md template updated to act on goal_guidance signals at session start
- CUST-WP-0010 workplan for this feature

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

api/routers/workstreams.py

@@ -15,6 +15,7 @@ router = APIRouter(prefix="/workstreams", tags=["workstreams"])
 async def list_workstreams(
     topic_id: uuid.UUID | None = None,
     repo_id: uuid.UUID | None = None,
+    repo_goal_id: uuid.UUID | None = None,
     status: WorkstreamStatus | None = None,
     session: AsyncSession = Depends(get_session),
 ) -> list[Workstream]:
@@ -23,9 +24,11 @@ async def list_workstreams(
         q = q.where(Workstream.topic_id == topic_id)
     if repo_id:
         q = q.where(Workstream.repo_id == repo_id)
+    if repo_goal_id:
+        q = q.where(Workstream.repo_goal_id == repo_goal_id)
     if status:
         q = q.where(Workstream.status == status)
-    q = q.order_by(Workstream.created_at)
+    q = q.order_by(Workstream.updated_at.desc())
     result = await session.execute(q)
     return list(result.scalars().all())