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>

tests/integration/test_chat_flow.py

@@ -0,0 +1,139 @@
+"""EPIC R08 - Chat UI Hub integration tests.
+
+Tests the lifecycle, UI component assembly, and event wiring of the refactored
+presentation/chat/ sub-package (ChatPanel, ComposerWidget, AudioRecorderWidget,
+ChatHistoryWidget, OutputPanelMixin).
+"""
+from __future__ import annotations
+
+import os
+from unittest.mock import MagicMock
+
+import pytest
+
+os.environ.setdefault("QT_QPA_PLATFORM", "offscreen")
+
+from cowork_local.config import AppConfig
+from cowork_local.presentation.chat import (
+    AudioRecorderWidget,
+    ChatHistoryWidget,
+    ChatPanel,
+    ChatView,
+    Composer,
+    ComposerWidget,
+    MessageBubble,
+)
+from cowork_local.state import AppContext
+
+pytest.importorskip("PySide6", reason="Qt required for chat UI integration tests")
+
+
+@pytest.fixture(scope="module")
+def qt_app():
+    from PySide6.QtWidgets import QApplication
+
+    return QApplication.instance() or QApplication([])
+
+
+@pytest.fixture
+def ctx(qt_app, tmp_path):
+    config_file = tmp_path / "config.json"
+    config = AppConfig.load(config_file)
+    return AppContext(config)
+
+
+def test_chat_history_widget_adds_and_clears_bubbles(qt_app):
+    """Verify ChatHistoryWidget / ChatView can append different bubble types and clear them."""
+    view = ChatHistoryWidget()
+    assert isinstance(view, ChatView)
+
+    b_user = view.add_user("Hello agent")
+    assert isinstance(b_user, MessageBubble)
+    assert b_user.role == "user"
+
+    b_assistant = view.add_assistant()
+    assert isinstance(b_assistant, MessageBubble)
+    assert b_assistant.role == "assistant"
+    b_assistant.set_markdown("**Bold response**")
+
+    b_status = view.add_status("Processing task...")
+    assert isinstance(b_status, MessageBubble)
+
+    b_error = view.add_error("Network timeout")
+    assert isinstance(b_error, MessageBubble)
+
+    # Clear transcript
+    view.clear()
+    assert view._lay.count() == 1  # only trailing stretch item remains
+
+
+def test_composer_widget_queue_and_submission(qt_app):
+    """Verify ComposerWidget / Composer handles text submission and parallel queueing."""
+    composer = ComposerWidget()
+    assert isinstance(composer, Composer)
+
+    submitted_events = []
+    composer.submitted.connect(lambda text, atts: submitted_events.append((text, atts)))
+
+    # Direct submission via _on_submit
+    composer.set_text("Run command ls")
+    composer._on_submit()
+    assert len(submitted_events) == 1
+    assert submitted_events[0][0] == "Run command ls"
+    assert submitted_events[0][1] == []
+
+    # Submit when busy puts message in queue
+    composer.set_busy(True)
+    composer.enqueue("Queued task 1")
+    composer.enqueue("Queued task 2", attachments=["/tmp/file.txt"])
+
+    assert len(composer._queue) == 2
+    assert composer.has_queue() is True
+
+    # Free up slot via pop_next
+    next_msg = composer.pop_next()
+    assert next_msg is not None
+    assert next_msg["text"] == "Queued task 1"
+    assert len(composer._queue) == 1
+
+
+def test_audio_recorder_widget_state_transitions(qt_app):
+    """Verify AudioRecorderWidget transitions from idle -> recording -> stopped."""
+    recorder = AudioRecorderWidget()
+    assert recorder.is_recording() is False
+
+    started_signal = MagicMock()
+    stopped_signal = MagicMock()
+    audio_ready_signal = MagicMock()
+
+    recorder.recording_started.connect(started_signal)
+    recorder.recording_stopped.connect(stopped_signal)
+    recorder.audio_ready.connect(audio_ready_signal)
+
+    # Start recording
+    recorder.start_recording()
+    assert recorder.is_recording() is True
+    started_signal.assert_called_once()
+
+    # Simulate timer tick
+    recorder._on_tick()
+    assert recorder.timer_label.text() == "00:01"
+
+    # Stop recording
+    recorder.stop_recording()
+    assert recorder.is_recording() is False
+    stopped_signal.assert_called_once_with(1)
+    audio_ready_signal.assert_called_once_with(b"", "wav")
+
+
+def test_chat_panel_initialization(ctx, qt_app):
+    """Verify ChatPanel builds correctly with its mixed-in panels and sub-widgets."""
+    panel = ChatPanel(ctx, kind="cowork", session_name="test_session")
+    assert panel.ctx is ctx
+    assert panel.kind == "cowork"
+    assert panel.session_name == "test_session"
+    assert hasattr(panel, "chat_view")
+    assert hasattr(panel, "composer")
+    assert hasattr(panel, "input_section")
+    assert hasattr(panel, "output_section")
+    assert isinstance(panel.composer, Composer)