feat(standalone): 新增单机模式，KILOSTAR_MODE=standalone 时去掉 Ray 依赖

通过 StandaloneProxy 适配层让 .remote() 调用在单机模式下透明降级为
asyncio 协程调用，7 个 Actor 和 workflow task 均可在纯 asyncio 环境运行，
启动快、资源占用低。分布式模式行为完全不变。

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

kilostar/core/individual/control_node/control_node.py

@@ -12,8 +12,8 @@
 #  See the License for the specific language governing permissions and
 #  limitations under the License.
 
-import ray
 from pydantic_ai import Agent, RunContext
+from kilostar.utils.standalone_proxy import actor_class
 from kilostar.core.global_state_machine.global_state_machine import GlobalStateMachine
 from kilostar.core.global_state_machine.model_provider.base_provider import Provider
 from kilostar.adapter.model_adapter.agent_factory import AgentFactory
@@ -25,7 +25,7 @@ from kilostar.core.individual.control_node.template import (
 from kilostar.utils.i18n import agent_prompt
 
 
-@ray.remote
+@actor_class
 class ControlNode:
     """ControlNode（控制节点）：工作流中具体子任务的执行 Actor。