feat: 新增工具插件、系统日志、workflow配置及前端优化

1. 新增工具插件(edit_file, python_executor, search_file, shell_executor, write_file)
2. 新增系统事件日志模块和API
3. 新增workflow配置文件和详情API
4. 前端增加SSE、错误边界、设置引导等组件
5. 优化认证加密、速率限制、配置加载等工具模块
6. 删除废弃的cluster和health API
7. 补充单元测试和集成测试

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

tests/unit/test_config_loader.py

@@ -0,0 +1,78 @@
+"""``utils/config_loader.py``：workflow.yaml 读/写/热重载。"""
+
+from __future__ import annotations
+
+import yaml
+import pytest
+
+
+@pytest.fixture(autouse=True)
+def isolated_yaml(tmp_path, monkeypatch):
+    """每个用例用独立的临时 yaml，避免污染真实 config/workflow.yaml。"""
+    from kilostar.utils import config_loader
+
+    fake_yaml = tmp_path / "workflow.yaml"
+    monkeypatch.setattr(config_loader, "_WORKFLOW_YAML", fake_yaml)
+    monkeypatch.setattr(config_loader, "_current", None)
+    return fake_yaml
+
+
+def test_get_workflow_config_returns_default_when_file_absent():
+    from kilostar.utils.config_loader import get_workflow_config
+
+    config = get_workflow_config()
+    assert config.retry.max_attempts == 5
+
+
+def test_get_workflow_config_reads_from_disk(isolated_yaml):
+    isolated_yaml.write_text("retry:\n  max_attempts: 12\n", encoding="utf-8")
+
+    from kilostar.utils.config_loader import reload_workflow_config
+
+    config = reload_workflow_config()
+    assert config.retry.max_attempts == 12
+
+
+def test_save_workflow_config_writes_yaml_and_reloads(isolated_yaml):
+    from kilostar.utils.config_loader import (
+        save_workflow_config,
+        get_workflow_config,
+        WorkflowConfig,
+        RetryConfig,
+    )
+
+    new_config = WorkflowConfig(retry=RetryConfig(max_attempts=20))
+    save_workflow_config(new_config)
+
+    on_disk = yaml.safe_load(isolated_yaml.read_text(encoding="utf-8"))
+    assert on_disk == {"retry": {"max_attempts": 20}}
+
+    # 热重载：再次 get 应直接拿到新值
+    assert get_workflow_config().retry.max_attempts == 20
+
+
+def test_max_attempts_validation_rejects_out_of_range():
+    from kilostar.utils.config_loader import RetryConfig
+
+    with pytest.raises(Exception):
+        RetryConfig(max_attempts=0)
+
+    with pytest.raises(Exception):
+        RetryConfig(max_attempts=200)
+
+
+def test_reload_picks_up_external_file_changes(isolated_yaml):
+    """模拟运维直接改 yaml 文件，reload 后引擎能拿到新值。"""
+    isolated_yaml.write_text("retry:\n  max_attempts: 3\n", encoding="utf-8")
+
+    from kilostar.utils.config_loader import (
+        get_workflow_config,
+        reload_workflow_config,
+    )
+
+    assert reload_workflow_config().retry.max_attempts == 3
+
+    isolated_yaml.write_text("retry:\n  max_attempts: 30\n", encoding="utf-8")
+    assert reload_workflow_config().retry.max_attempts == 30
+    # get_workflow_config 也读到最新
+    assert get_workflow_config().retry.max_attempts == 30