feat: 添加 OpenAI 兼容 API 支持和独立 Vision 服务

- 添加 OpenAI AI SDK provider 支持 (@ai-sdk/openai)
- 支持 OpenAI 兼容服务的 baseUrl 配置（如阿里云百炼）
- 添加独立的 Vision 配置（visionProvider/visionApiKey/visionBaseUrl/visionModel）
- 实现图片引用语法 @path/to/image.png，支持带空格的路径
- 当主模型不支持 vision 时，自动调用配置的 Vision 服务分析图片
- 添加图片处理工具函数和单元测试

src/core/agent.ts

@@ -1,5 +1,6 @@
 import { createAnthropic } from '@ai-sdk/anthropic';
 import { createDeepSeek } from '@ai-sdk/deepseek';
+import { createOpenAI } from '@ai-sdk/openai';
 import {
   generateText,
   streamText,
@@ -8,7 +9,7 @@ import {
   type Tool as AITool,
   type LanguageModel,
 } from 'ai';
-import type { Tool, ToolResult, Message, AgentConfig, ProviderType } from '../types/index.js';
+import type { Tool, ToolResult, Message, AgentConfig, ProviderType, UserInput, ContentBlock } from '../types/index.js';
 import { buildZodSchema } from '../types/index.js';
 import { ToolRegistry } from '../tools/registry.js';
 import { SessionManager } from '../session/index.js';
@@ -19,17 +20,27 @@ import {
 } from '../context/index.js';
 import type { AgentInfo } from '../agent/types.js';
 
+// Provider 配置
+interface ProviderOptions {
+  apiKey: string;
+  baseUrl?: string;
+}
+
 // Provider 工厂函数类型
-type ProviderFactory = (apiKey: string) => (model: string) => LanguageModel;
+type ProviderFactory = (options: ProviderOptions) => (model: string) => LanguageModel;
 
 // Provider 注册表
 const providers: Record<ProviderType, ProviderFactory> = {
-  anthropic: (apiKey) => {
-    const client = createAnthropic({ apiKey });
+  anthropic: ({ apiKey, baseUrl }) => {
+    const client = createAnthropic({ apiKey, baseURL: baseUrl });
     return (model) => client(model);
   },
-  deepseek: (apiKey) => {
-    const client = createDeepSeek({ apiKey });
+  deepseek: ({ apiKey, baseUrl }) => {
+    const client = createDeepSeek({ apiKey, baseURL: baseUrl });
+    return (model) => client(model);
+  },
+  openai: ({ apiKey, baseUrl }) => {
+    const client = createOpenAI({ apiKey, baseURL: baseUrl });
     return (model) => client(model);
   },
 };
@@ -68,7 +79,7 @@ export class Agent {
     if (!providerFactory) {
       throw new Error(`不支持的 provider: ${config.provider}`);
     }
-    this.getModel = providerFactory(config.apiKey);
+    this.getModel = providerFactory({ apiKey: config.apiKey, baseUrl: config.baseUrl });
 
     // 初始化压缩管理器
     this.compressionManager = new CompressionManager(compressionConfig);
@@ -221,13 +232,49 @@ export class Agent {
 
   /**
    * 发送消息并处理响应（流式）
+   * @param userMessage 用户消息文本或包含图片的 UserInput
+   * @param onStream 流式输出回调
    */
-  async chat(userMessage: string, onStream?: (text: string) => void): Promise<string> {
+  async chat(userMessage: string | UserInput, onStream?: (text: string) => void): Promise<string> {
+    // 构建消息内容
+    let messageContent: string | ContentBlock[];
+
+    if (typeof userMessage === 'string') {
+      // 纯文本消息
+      messageContent = userMessage;
+    } else {
+      // 带图片的消息
+      const blocks: ContentBlock[] = [];
+
+      // 添加图片
+      if (userMessage.images && userMessage.images.length > 0) {
+        for (const img of userMessage.images) {
+          blocks.push({
+            type: 'image',
+            image: img.data,
+            mimeType: img.mimeType,
+          });
+        }
+      }
+
+      // 添加文本
+      if (userMessage.text) {
+        blocks.push({
+          type: 'text',
+          text: userMessage.text,
+        });
+      }
+
+      messageContent = blocks.length === 1 && blocks[0].type === 'text'
+        ? blocks[0].text
+        : blocks;
+    }
+
     // 添加用户消息到历史
     this.conversationHistory.push({
       role: 'user',
-      content: userMessage,
-    });
+      content: messageContent,
+    } as ModelMessage);
 
     const vercelTools = this.getVercelTools();
     let fullResponse = '';
@@ -436,4 +483,37 @@ export class Agent {
   getAgentModeName(): string {
     return this.currentAgentMode?.name ?? 'default';
   }
+
+  /**
+   * 检查当前模型是否支持 vision（图片理解）
+   */
+  supportsVision(): boolean {
+    const model = this.config.model.toLowerCase();
+
+    // Anthropic Claude 模型支持 vision
+    if (this.config.provider === 'anthropic') {
+      // Claude 3 及以上版本支持 vision
+      return model.includes('claude-3') || model.includes('claude-4');
+    }
+
+    // OpenAI GPT-4 系列支持 vision
+    if (this.config.provider === 'openai') {
+      // GPT-4o, GPT-4 Turbo, GPT-4 Vision 等支持
+      return model.includes('gpt-4');
+    }
+
+    // DeepSeek 目前不支持 vision
+    if (this.config.provider === 'deepseek') {
+      return false;
+    }
+
+    return false;
+  }
+
+  /**
+   * 获取当前配置
+   */
+  getConfig(): AgentConfig {
+    return { ...this.config };
+  }
 }