feat: Implement AI Agent with enhanced tool processing capabilities (#89)

* feat: Implement AI Agent with tool processing capabilities

- Added tools for listing and running processors in the agent.
- Created data models for agent chat requests and tool calls.
- Developed API integration for agent chat and streaming responses.
- Built the AI Agent widget with a user interface for interaction.
- Styled the agent components for better user experience.

* feat: 增强 AI 助手工具功能，添加文件操作和搜索功能，更新界面显示

* feat: 更新 AI 助手组件

* feat: 更新 AiAgentWidget 组件样式，调整背景和边距以提升界面一致性

domain/agent/types.py

@@ -0,0 +1,23 @@
+from typing import Any, Dict, List, Optional
+
+from pydantic import BaseModel, Field
+
+
+class AgentChatContext(BaseModel):
+    current_path: Optional[str] = None
+
+
+class AgentChatRequest(BaseModel):
+    messages: List[Dict[str, Any]] = Field(default_factory=list)
+    auto_execute: bool = False
+    approved_tool_call_ids: List[str] = Field(default_factory=list)
+    rejected_tool_call_ids: List[str] = Field(default_factory=list)
+    context: Optional[AgentChatContext] = None
+
+
+class PendingToolCall(BaseModel):
+    id: str
+    name: str
+    arguments: Dict[str, Any] = Field(default_factory=dict)
+    requires_confirmation: bool = True
+