feat: v3.0 Tool Calling — AI 本地文件操作系统

新增文件:
- src/main/tool-security.ts: 路径白名单/黑名单、命令安全检查
- src/main/tool-handlers.ts: 7个工具实现(read/write/list/search/create/delete/run)
- src/renderer/services/tool-registry.ts: 工具注册调度中心
- src/renderer/services/agent-engine.ts: Agent Loop 流式多轮工具调用引擎
- src/renderer/components/tool-confirm-modal.ts: 高风险操作确认对话框

修改文件:
- types.d.ts: 新增 ToolCall/ToolResult/ToolCallRecord 等类型
- ollama.ts: chatStream 支持 tools 参数
- ipc.ts: 新增 tool:execute/getConfig/setAllowedDirs IPC
- preload.ts: 暴露 tool API
- chat-area.ts: 渲染工具调用卡片
- input-area.ts: 集成 Agent Loop 引擎
- settings-modal.ts: 工具调用开关设置
- index.html: 工具调用设置面板 + 确认对话框 HTML
- style.css: 工具调用卡片、确认对话框样式
- main.ts: 初始化工具调用配置

src/renderer/api/ollama.ts

@@ -5,7 +5,7 @@
 import type {
   OllamaChatParams, OllamaStreamChunk, OllamaModelsResponse,
   OllamaPsResponse, OllamaVersionResponse, OllamaModelDetail,
-  OllamaEmbedResponse
+  OllamaEmbedResponse, ToolDefinition
 } from '../types.js';
 
 export class OllamaAPI {
@@ -65,7 +65,7 @@ export class OllamaAPI {
   }
 
   async chatStream(
-    params: OllamaChatParams,
+    params: OllamaChatParams & { tools?: ToolDefinition[] },
     onChunk: (chunk: OllamaStreamChunk) => void,
     abortController?: AbortController
   ): Promise<void> {
@@ -78,6 +78,7 @@ export class OllamaAPI {
     if (params.system) body.system = params.system;
     if (params.keep_alive !== undefined) body.keep_alive = params.keep_alive;
     if (params.options) body.options = params.options;
+    if (params.tools?.length) body.tools = params.tools;
 
     const fetchOptions: RequestInit = {
       method: 'POST',