Feature/delta team/epic r04 (#7)

## Summary

epic r04 - begin refactor

## Change Type

- [x] Cowork feature
- [ ] Bug fix
- [ ] Core AI contribution
- [ ] Test / hardening
- [ ] Performance
- [ ] Documentation

## Related Work

Cowork Task:

Core Repo: http://34.143.229.138/gitea-admin/fsg-ai-core-assets

Core AI Issue:

Core Task:

Related PR:

## Scope

What is intentionally included?

What is intentionally NOT included?

## Validation

- [ ] Unit tests
- [ ] Integration tests
- [ ] Manual verification
- [ ] Regression check

Commands / evidence:

## Security Impact

Permission / credential / network / customer data impact:

## Compatibility

- [ ] No breaking change
- [ ] Breaking change documented

## Reviewer Notes

Anything Cowork reviewers should pay attention to.

---------

Co-authored-by: Anh Tran Nguyen Minh <anhtnm1@fpt.com>
Co-authored-by: Huong Le Thi Thien <huongltt35@fpt.com>
Co-authored-by: Nam Pham Dinh Thanh <nampdt@fpt.com>
Co-authored-by: Vu Dam Tuan <vudt15@fpt.com>
Co-authored-by: Hiep Ha Van <hiephv3@fpt.com>
Co-authored-by: Lam Hoang Van <lamhv7@fpt.com>
Reviewed-on: #7
Co-authored-by: Duy Le Huu <duylh19@fpt.com>

domain/agents/__init__.py

@@ -0,0 +1,51 @@
+"""Domain agents package: turn requests, agent events, and role definitions."""
+
+from .agent_event import (
+    NOTICE_INFO,
+    NOTICE_PROGRESS,
+    NOTICE_WARNING,
+    AgentEvent,
+    AssistantMessageCompletedEvent,
+    ErrorEvent,
+    HistoryReadyEvent,
+    NoticeEvent,
+    OutputsAddedEvent,
+    OutputsRemovedEvent,
+    PlanStep,
+    PlanUpdatedEvent,
+    ReasoningChunkEvent,
+    TextChunkEvent,
+    ToolCallFinishedEvent,
+    ToolCallStartedEvent,
+    ToolOutputChunkEvent,
+    ToolPreview,
+    TurnCompletedEvent,
+)
+from .conversation_execution_request import (
+    PREFIX_SEPARATOR,
+    ConversationExecutionRequest,
+)
+
+__all__ = [
+    "NOTICE_INFO",
+    "NOTICE_PROGRESS",
+    "NOTICE_WARNING",
+    "PREFIX_SEPARATOR",
+    "AgentEvent",
+    "AssistantMessageCompletedEvent",
+    "ConversationExecutionRequest",
+    "ErrorEvent",
+    "HistoryReadyEvent",
+    "NoticeEvent",
+    "OutputsAddedEvent",
+    "OutputsRemovedEvent",
+    "PlanStep",
+    "PlanUpdatedEvent",
+    "ReasoningChunkEvent",
+    "TextChunkEvent",
+    "ToolCallFinishedEvent",
+    "ToolCallStartedEvent",
+    "ToolOutputChunkEvent",
+    "ToolPreview",
+    "TurnCompletedEvent",
+]