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- Delete superseded plan docs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/src/v1/memory/repository.py

@@ -0,0 +1,35 @@
+from __future__ import annotations
+
+from typing import TYPE_CHECKING, Protocol
+from uuid import UUID
+
+from sqlalchemy import select
+
+from core.db.base_repository import BaseRepository
+from models.automation_jobs import AutomationJob
+
+if TYPE_CHECKING:
+    from sqlalchemy.ext.asyncio import AsyncSession
+
+
+class MemoryRepositoryLike(Protocol):
+    async def get_job_by_id_and_owner(
+        self, *, job_id: UUID, owner_id: UUID
+    ) -> AutomationJob | None: ...
+
+
+class MemoryRepository(BaseRepository[AutomationJob]):
+    def __init__(self, session: AsyncSession) -> None:
+        super().__init__(session=session, model=AutomationJob)
+
+    async def get_job_by_id_and_owner(
+        self, *, job_id: UUID, owner_id: UUID
+    ) -> AutomationJob | None:
+        stmt = (
+            select(AutomationJob)
+            .where(AutomationJob.id == job_id)
+            .where(AutomationJob.owner_id == owner_id)
+            .where(AutomationJob.deleted_at.is_(None))
+        )
+        result = await self._session.execute(stmt)
+        return result.scalar_one_or_none()