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- DomainGoal: one active per domain (partial unique index), status active/archived/superseded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/models/domain_goal.py

@@ -0,0 +1,41 @@
+import enum
+import uuid
+
+from sqlalchemy import ForeignKey, String, Text
+from sqlalchemy.dialects.postgresql import UUID
+from sqlalchemy.orm import Mapped, mapped_column, relationship
+
+from api.models.base import Base, TimestampMixin, new_uuid
+
+
+class DomainGoalStatus(str, enum.Enum):
+    active = "active"
+    archived = "archived"
+    superseded = "superseded"
+
+
+class DomainGoal(Base, TimestampMixin):
+    __tablename__ = "domain_goals"
+
+    id: Mapped[uuid.UUID] = mapped_column(
+        UUID(as_uuid=True), primary_key=True, default=new_uuid
+    )
+    domain_id: Mapped[uuid.UUID] = mapped_column(
+        UUID(as_uuid=True), ForeignKey("domains.id", ondelete="RESTRICT"), nullable=False, index=True
+    )
+    title: Mapped[str] = mapped_column(String(500), nullable=False)
+    description: Mapped[str] = mapped_column(Text, nullable=False)
+    status: Mapped[str] = mapped_column(
+        String(20), nullable=False, default=DomainGoalStatus.active.value, server_default="active"
+    )
+
+    domain: Mapped["Domain"] = relationship(  # noqa: F821
+        "Domain", back_populates="goals", lazy="selectin"
+    )
+    repo_goals: Mapped[list["RepoGoal"]] = relationship(  # noqa: F821
+        "RepoGoal", back_populates="domain_goal", lazy="selectin"
+    )
+
+    @property
+    def domain_slug(self) -> str:
+        return self.domain.slug if self.domain is not None else ""