refactor(agent): restructure visibility masks, task queues, and memory service

Visibility mask refactoring:
- Replace dead UI_REALTIME bit with CONTEXT_ASSEMBLY (bit 1)
- Remove visibility_consumer_bit from SystemAgentLLMConfig and system_agents.yaml
- Simplify _resolve_user_message_visibility_mask: chat->UI_HISTORY|CONTEXT_ASSEMBLY, automation->0
- Simplify _resolve_stage_visibility_mask: memory->UI_HISTORY, router/worker->UI_HISTORY|CONTEXT_ASSEMBLY
- Remove stage_visibility_bit_map from store.py

Task queue renaming:
- Replace default_broker/bulk_broker/critical_broker with worker_agent_broker/worker_automation_broker
- Queue names: 'default'/'bulk'/'critical' -> 'agent'/'automation'
- Rename run_command_task -> run_command_task_agent/run_command_task_automation
- AgentService derives queue from runtime_mode: chat->agent, automation->automation

Architecture cleanup:
- Move context_service.py from runtime/ to agentscope/services/
- Add MemoryService in v1/memory/ following repository/service pattern
- Move consumer_registry.py and pipeline_spec.py from schemas/agent to agentscope/schemas/
- Delete dead code: registry_builder.py, VisibilityBitRef
- Delete superseded plan docs

backend/tests/unit/schemas/agent/test_pipeline_spec.py

@@ -2,13 +2,12 @@ from __future__ import annotations
 
 import pytest
 
-from schemas.agent.consumer_registry import AgentConsumerBinding, ConsumerRegistry
-from schemas.agent.pipeline_spec import (
-    ContextPolicy,
-    ExecutorKind,
-    PipelineSpec,
-    StageSpec,
+from core.agentscope.schemas.consumer_registry import (
+    AgentConsumerBinding,
+    ConsumerRegistry,
 )
+from core.agentscope.schemas.pipeline_spec import ExecutorKind, PipelineSpec, StageSpec
+from schemas.agent.system_agent import AgentType
 
 
 def test_consumer_registry_rejects_duplicate_bits() -> None:
@@ -29,9 +28,9 @@ def test_pipeline_spec_requires_non_empty_stages() -> None:
 def test_stage_spec_normalizes_stage_name() -> None:
     spec = StageSpec(
         stage_name=" Worker ",
+        agent_type=AgentType.WORKER,
         executor_kind=ExecutorKind.REACT,
-        default_visibility_mask=1,
-        context_policy=ContextPolicy(consumer_agent_type="worker", count=20),
     )
 
     assert spec.stage_name == "worker"
+    assert spec.agent_type == AgentType.WORKER