refactor(core): 统一配置系统，移除 config.json

- 移除 config.json，所有配置统一从 agents.json 和 providers.json 读取
- config-loader.ts 从全局目录 ~/.ai-terminal-assistant/ 加载配置
- loadConfig() 从 agentRegistry.getGlobalConfig() 获取 defaults.model
- 添加 loadVisionConfig() 支持 Vision 模型配置
- Tavily API Key 仅从环境变量读取
- UI AgentDefaultsEditor 添加 Vision 模型配置界面
- 更新相关测试

packages/core/tests/unit/tools/web/web_extract.test.ts

@@ -8,12 +8,8 @@ vi.mock('@tavily/core', () => ({
   })),
 }));
 
-// Mock config
-vi.mock('../../../../src/utils/config.js', () => ({
-  getConfig: vi.fn(() => ({
-    tavilyApiKey: 'test-api-key',
-  })),
-}));
+// Mock environment variable for Tavily API Key
+vi.stubEnv('TAVILY_API_KEY', 'test-api-key');
 
 // Mock permission manager
 vi.mock('../../../../src/permission/index.js', () => ({
@@ -32,7 +28,6 @@ vi.mock('../../../../src/tools/load_description.js', () => ({
 
 import { webExtractTool } from '../../../../src/tools/web/web_extract.js';
 import { getPermissionManager } from '../../../../src/permission/index.js';
-import { getConfig } from '../../../../src/utils/config.js';
 
 describe('webExtractTool - 网页内容提取工具', () => {
   beforeEach(() => {
@@ -198,9 +193,7 @@ describe('webExtractTool - 网页内容提取工具', () => {
     });
 
     it('无 API Key 返回错误', async () => {
-      vi.mocked(getConfig).mockReturnValue({} as any);
-      const originalEnv = process.env.TAVILY_API_KEY;
-      delete process.env.TAVILY_API_KEY;
+      vi.unstubAllEnvs();
 
       const result = await webExtractTool.execute({
         urls: ['https://example.com'],
@@ -209,7 +202,7 @@ describe('webExtractTool - 网页内容提取工具', () => {
       expect(result.success).toBe(false);
       expect(result.error).toContain('未配置 Tavily API Key');
 
-      process.env.TAVILY_API_KEY = originalEnv;
+      vi.stubEnv('TAVILY_API_KEY', 'test-api-key');
     });
 
     it('权限被拒绝时返回错误', async () => {

packages/core/tests/unit/tools/web/web_search.test.ts

@@ -8,12 +8,8 @@ vi.mock('@tavily/core', () => ({
   })),
 }));
 
-// Mock config
-vi.mock('../../../../src/utils/config.js', () => ({
-  getConfig: vi.fn(() => ({
-    tavilyApiKey: 'test-api-key',
-  })),
-}));
+// Mock environment variable for Tavily API Key
+vi.stubEnv('TAVILY_API_KEY', 'test-api-key');
 
 // Mock permission manager
 vi.mock('../../../../src/permission/index.js', () => ({
@@ -32,7 +28,6 @@ vi.mock('../../../../src/tools/load_description.js', () => ({
 
 import { webSearchTool } from '../../../../src/tools/web/web_search.js';
 import { getPermissionManager } from '../../../../src/permission/index.js';
-import { getConfig } from '../../../../src/utils/config.js';
 
 describe('webSearchTool - 网络搜索工具', () => {
   beforeEach(() => {
@@ -131,16 +126,14 @@ describe('webSearchTool - 网络搜索工具', () => {
     });
 
     it('无 API Key 返回错误', async () => {
-      vi.mocked(getConfig).mockReturnValue({} as any);
-      const originalEnv = process.env.TAVILY_API_KEY;
-      delete process.env.TAVILY_API_KEY;
+      vi.unstubAllEnvs();
 
       const result = await webSearchTool.execute({ query: 'test' });
 
       expect(result.success).toBe(false);
       expect(result.error).toContain('未配置 Tavily API Key');
 
-      process.env.TAVILY_API_KEY = originalEnv;
+      vi.stubEnv('TAVILY_API_KEY', 'test-api-key');
     });
 
     it('权限被拒绝时返回错误', async () => {