refactor(JsonTools): 规范化页面组件目录结构

- 将子组件移至 components/ 子目录（JsonDiffInput、DiffResult、JsonFormatSection、JsonConvertSection、DiffNavigator、JsonTree）
- 将 diffEngine.ts 工具函数移至 src/utils/
- 提取 ConvertFunction/ConvertResult 类型到 types.ts，解决循环依赖
- 创建 __tests__/ 目录结构
- 更新所有相关导入路径

Co-authored-by: Cursor <cursoragent@cursor.com>

src/pages/JsonTools/components/JsonDiffInput.tsx

@@ -0,0 +1,42 @@
+import React from 'react';
+import TextInputArea from '@/components/TextInputArea';
+import { cn } from '@/lib/utils';
+
+export interface JsonDiffInputProps extends Omit<React.HTMLAttributes<HTMLDivElement>, 'onChange'> {
+  label: string;
+  placeholder: string;
+  value: string;
+  onChange: (value: string) => void;
+  error?: string | null;
+  minRows?: number;
+}
+
+export default function JsonDiffInput({
+  label,
+  placeholder,
+  value,
+  onChange,
+  error,
+  minRows = 10,
+  className,
+  ...props
+}: JsonDiffInputProps) {
+  return (
+    <div className={cn('flex-1 min-w-0 flex flex-col', className)} {...props}>
+      <span className="block mb-2 text-[10px] font-bold tracking-wide text-muted-foreground/80 uppercase select-none px-0.5">
+        {label}
+      </span>
+
+      <TextInputArea
+        value={value}
+        onChange={onChange}
+        placeholder={placeholder}
+        minRows={minRows}
+        maxRows={16}
+        externalError={error ?? undefined}
+        showClear={true}
+        allowCopy={true}
+      />
+    </div>
+  );
+}