Implement ACTIVITY-WP-0026 ops_run claim queue (T01–T06).

Add durable claimable ops_runs table, emit dual-write on TaskSpec, REST
claim/lease/complete/fail API, ops status visibility, and consumer docs
aligned with ACT-ADR-005. T07 railiance rollout remains deploy-side.

src/activity_core/orm.py

@@ -138,3 +138,45 @@ class TaskInstance(Base):
     created_at: Mapped[datetime] = mapped_column(
         DateTime(timezone=True), nullable=False, server_default=func.now()
     )
+
+
+class OpsRun(Base):
+    """Claimable automation run instance (ACT-ADR-005 / ACTIVITY-WP-0026)."""
+
+    __tablename__ = "ops_runs"
+
+    id: Mapped[uuid.UUID] = mapped_column(
+        UUID(as_uuid=True), primary_key=True, default=uuid.uuid4
+    )
+    activity_definition_id: Mapped[uuid.UUID] = mapped_column(
+        UUID(as_uuid=True),
+        ForeignKey("activity_definitions.id", ondelete="RESTRICT"),
+        nullable=False,
+        index=True,
+    )
+    idempotency_key: Mapped[str] = mapped_column(Text, nullable=False, unique=True)
+    target_repo: Mapped[str | None] = mapped_column(Text, nullable=True)
+    title: Mapped[str] = mapped_column(Text, nullable=False)
+    description: Mapped[str] = mapped_column(Text, nullable=False, default="")
+    labels: Mapped[list] = mapped_column(JSONB, nullable=False, default=list)
+    priority: Mapped[str] = mapped_column(Text, nullable=False, default="medium")
+    state: Mapped[str] = mapped_column(Text, nullable=False, default="open", index=True)
+    claim_owner: Mapped[str | None] = mapped_column(Text, nullable=True)
+    lease_until: Mapped[datetime | None] = mapped_column(
+        DateTime(timezone=True), nullable=True, index=True
+    )
+    attempt: Mapped[int] = mapped_column(Integer, nullable=False, default=0)
+    source_type: Mapped[str] = mapped_column(Text, nullable=False)
+    source_id: Mapped[str] = mapped_column(Text, nullable=False)
+    triggering_event_id: Mapped[str] = mapped_column(Text, nullable=False, index=True)
+    approach_hint: Mapped[str | None] = mapped_column(Text, nullable=True)
+    result: Mapped[dict] = mapped_column(JSONB, nullable=False, default=dict)
+    created_at: Mapped[datetime] = mapped_column(
+        DateTime(timezone=True), nullable=False, server_default=func.now()
+    )
+    updated_at: Mapped[datetime] = mapped_column(
+        DateTime(timezone=True),
+        nullable=False,
+        server_default=func.now(),
+        onupdate=func.now(),
+    )