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/server/src/agent/adapter.ts

@@ -12,6 +12,7 @@ import { getSessionManager } from '../session/manager.js';
 import { broadcastToSession } from '../ws.js';
 import { emitStatusEvent, emitLogEvent } from '../sse.js';
 import { createServerPermissionCallback, setSessionAutoApprove } from '../permission/handler.js';
+import { getConfig } from '../routes/config.js';
 
 // ============================================================================
 // Core 模块接口定义（避免直接依赖 @ai-assistant/core 类型）
@@ -220,18 +221,22 @@ export async function initCore(): Promise<boolean> {
       return false;
     }
 
+    // 获取服务器配置的工作目录
+    const config = getConfig();
+    const workdir = config.workdir;
+
     // 初始化 ProviderRegistry（加载用户配置）
     const providerRegistry = core.getProviderRegistry();
     if (!providerRegistry.isInitialized()) {
-      await providerRegistry.init();
-      console.log('[Agent] ProviderRegistry initialized');
+      await providerRegistry.init(workdir);
+      console.log('[Agent] ProviderRegistry initialized with workdir:', workdir);
     }
 
     // 初始化 AgentRegistry（加载用户自定义 Agent 配置）
     const agentRegistry = core.agentRegistry;
     if (!agentRegistry.isInitialized()) {
-      await agentRegistry.init(process.cwd());
-      console.log('[Agent] AgentRegistry initialized');
+      await agentRegistry.init(workdir);
+      console.log('[Agent] AgentRegistry initialized with workdir:', workdir);
     }
 
     coreModule = core;

packages/server/src/routes/providers.ts

@@ -5,6 +5,7 @@
  */
 
 import { Hono } from 'hono';
+import { getConfig } from './config.js';
 
 // Types from core - dynamically import to avoid build dependency
 interface ProviderListItem {
@@ -246,7 +247,7 @@ providersRouter.post('/', async (c) => {
 
     const registry = core.getProviderRegistry();
     registry.registerCustom(body);
-    await registry.saveConfig();
+    await registry.saveConfig(getConfig().workdir);
 
     return c.json({
       success: true,
@@ -284,7 +285,7 @@ providersRouter.put('/:id', async (c) => {
     }
 
     registry.setConfig(id, { ...body, id });
-    await registry.saveConfig();
+    await registry.saveConfig(getConfig().workdir);
 
     return c.json({
       success: true,
@@ -320,7 +321,7 @@ providersRouter.delete('/:id', async (c) => {
       return c.json({ success: false, error: `Provider not found: ${id}` }, 404);
     }
 
-    await registry.saveConfig();
+    await registry.saveConfig(getConfig().workdir);
 
     return c.json({
       success: true,
@@ -364,7 +365,7 @@ providersRouter.post('/:id/models', async (c) => {
 
     const registry = core.getProviderRegistry();
     registry.addCustomModel(providerId, body);
-    await registry.saveConfig();
+    await registry.saveConfig(getConfig().workdir);
 
     return c.json({
       success: true,
@@ -407,7 +408,7 @@ providersRouter.delete('/:id/models/:modelId', async (c) => {
       );
     }
 
-    await registry.saveConfig();
+    await registry.saveConfig(getConfig().workdir);
 
     return c.json({
       success: true,