chore: 更新项目配置和依赖，优化前后端代码

src/utils/convert.js

@@ -1,7 +1,5 @@
 import { CONVERT_URL } from './config.js'
 
-const API_KEY = 'your-secret-key-here'
-
 function readFileAsBase64(file) {
     return new Promise((resolve, reject) => {
         const reader = new FileReader()
@@ -25,7 +23,6 @@ export async function convertFileToMarkdown(file) {
         method: 'POST',
         headers: {
             'Content-Type': 'application/json',
-            'X-API-Key': API_KEY,
         },
         body: JSON.stringify({
             file: base64,