feat(permission): 实现 WebSocket 权限确认机制

重构权限系统，将终端 UI 代码从 core 模块移除，实现基于 WebSocket 的权限确认流程：

Core 模块清理：
- 删除 permission/prompt.ts 和 file-prompt.ts（终端交互）
- 删除 diff.ts 中的 chalk 渲染函数
- 删除 config.ts 中的 inquirer 交互
- 移除 chalk 依赖

Server 权限处理：
- 新增 permission/handler.ts，实现 WebSocket 权限请求/响应
- 更新 agent/adapter.ts 设置权限回调
- 更新 ws.ts 处理 permission_response 消息

Web 权限组件：
- 新增 PermissionDialog 组件，显示权限请求详情和 Diff
- 更新 useChat hook 管理权限状态
- 更新 Chat 页面集成权限弹窗

packages/core/tests/unit/utils/diff.test.ts

@@ -1,5 +1,5 @@
 import { describe, it, expect } from 'vitest';
-import { computeDiff, countChanges, formatEditDiff, formatDiff } from '../../../src/utils/diff.js';
+import { computeDiff, countChanges } from '../../../src/utils/diff.js';
 
 describe('computeDiff - 计算文件差异', () => {
   describe('新文件', () => {
@@ -156,31 +156,6 @@ describe('countChanges - 统计变更数量', () => {
   });
 });
 
-describe('formatEditDiff - 格式化编辑差异', () => {
-  it('显示删除和新增内容', () => {
-    const result = formatEditDiff('old text', 'new text');
-
-    expect(result).toContain('变更内容');
-    expect(result).toContain('old text');
-    expect(result).toContain('new text');
-  });
-
-  it('多行内容正确显示', () => {
-    const result = formatEditDiff('line1\nline2', 'new1\nnew2\nnew3');
-
-    expect(result).toContain('line1');
-    expect(result).toContain('line2');
-    expect(result).toContain('new1');
-    expect(result).toContain('new2');
-    expect(result).toContain('new3');
-  });
-
-  it('空内容处理', () => {
-    const result = formatEditDiff('', 'new');
-
-    expect(result).toContain('new');
-  });
-});
 
 describe('DiffResult 结构', () => {
   it('包含所有必要字段', () => {
@@ -248,55 +223,6 @@ describe('LCS 算法测试', () => {
   });
 });
 
-describe('formatDiff - 格式化 diff 输出', () => {
-  it('新文件显示新增标记', () => {
-    const diff = computeDiff(null, 'line1\nline2');
-    const result = formatDiff(diff, '/test/file.ts');
-
-    expect(result).toContain('新文件');
-    expect(result).toContain('/test/file.ts');
-  });
-
-  it('修改文件显示原文件和修改后标记', () => {
-    const diff = computeDiff('old', 'new');
-    const result = formatDiff(diff, '/test/file.ts');
-
-    expect(result).toContain('原文件');
-    expect(result).toContain('修改后');
-    expect(result).toContain('/test/file.ts');
-  });
-
-  it('hunk 头部显示正确的行号范围', () => {
-    const diff = computeDiff('line1\nline2', 'line1\nnew\nline2');
-    const result = formatDiff(diff, '/test/file.ts');
-
-    expect(result).toContain('@@');
-  });
-
-  it('新增行显示 + 前缀', () => {
-    const diff = computeDiff(null, 'added line');
-    const result = formatDiff(diff, '/test/file.ts');
-
-    expect(result).toContain('+');
-    expect(result).toContain('added line');
-  });
-
-  it('删除行显示 - 前缀', () => {
-    const diff = computeDiff('removed line', 'new line');
-    const result = formatDiff(diff, '/test/file.ts');
-
-    expect(result).toContain('-');
-    expect(result).toContain('removed line');
-  });
-
-  it('空 diff 返回基本格式', () => {
-    const diff = computeDiff('same', 'same');
-    const result = formatDiff(diff, '/test/file.ts');
-
-    // 没有 hunks 时只有头部
-    expect(result).toContain('/test/file.ts');
-  });
-});
 
 describe('实际代码场景', () => {
   it('函数修改', () => {