feat: implement user generation tracking and GitHub star validation for license key generation

- Added UserGeneration model to track user license generation counts and statuses.
- Introduced validateStar utility to check if a user has starred the project on GitHub.
- Updated license key generation endpoint to validate user star status and manage generation limits.
- Refactored server.js to handle new user generation logic and improved error handling.

server/utils/validateStar.js

@@ -0,0 +1,30 @@
+async function validateStar(username) {
+  try {
+    const response = await fetch(`https://api.github.com/users/${username}/starred`);
+    
+    if (response.ok) {
+      const data = await response.json();
+      const hasStarred = data.some(repo => repo.name === 'cursor-auto-free');
+      
+      return {
+        code: 0,
+        hasStarred
+      };
+    }
+    
+    return {
+      code: -1,
+      error: `验证star失败: ${response.status}`
+    };
+
+  } catch (error) {
+    return {
+      code: -1,
+      error: `请求出错: ${error.message}`
+    };
+  }
+}
+
+module.exports = {
+  validateStar
+};