refactor: 清理所有调试日志和死代码

- 🗑️ 删除未使用的依赖: net, dns 模块
- 🧹 将 console.log("[DEBUG]") 替换为 SystemLogDB.log()
- 🧹 清理分享验证相关的调试日志
- 🧹 清理数据库查询的调试日志
- 🧹 删除下载功能的调试日志
- ✅ 代码更专业，日志统一使用 SystemLogDB

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

backend/database.js

@@ -441,14 +441,6 @@ const ShareDB = {
 
   // 根据分享码查找
   findByCode(shareCode) {
-    // 调试日志: findByCode 调用
-    const currentTime = db.prepare("SELECT datetime('now', 'localtime') as now").get();
-    console.log('[ShareDB.findByCode]', {
-      shareCode,
-      currentTime: currentTime.now,
-      timestamp: new Date().toISOString()
-    });
-
     const result = db.prepare(`
       SELECT s.*, u.username, u.oss_provider, u.oss_region, u.oss_access_key_id, u.oss_access_key_secret, u.oss_bucket, u.oss_endpoint, u.theme_preference
       FROM shares s
@@ -457,14 +449,6 @@ const ShareDB = {
         AND (s.expires_at IS NULL OR s.expires_at > datetime('now', 'localtime'))
     `).get(shareCode);
 
-    // 调试日志: SQL查询结果
-    console.log('[ShareDB.findByCode] SQL结果:', {
-      found: !!result,
-      shareCode: result?.share_code || null,
-      expires_at: result?.expires_at || null,
-      share_type: result?.share_type || null
-    });
-
     return result;
   },
 

backend/server.js

@@ -13,8 +13,6 @@ const fs = require('fs');
 const { body, validationResult } = require('express-validator');
 const archiver = require('archiver');
 const { exec, execSync, execFile } = require('child_process');
-const net = require('net');
-const dns = require('dns').promises;
 const util = require('util');
 const execAsync = util.promisify(exec);
 const execFileAsync = util.promisify(execFile);
@@ -3208,7 +3206,13 @@ app.post('/api/upload/get-config', async (req, res) => {
 app.post('/api/share/create', authMiddleware, (req, res) => {
   try {
     const { share_type, file_path, file_name, password, expiry_days } = req.body;
-    console.log("[DEBUG] 创建分享请求:", { share_type, file_path, file_name, password: password ? "***" : null, expiry_days });
+    SystemLogDB.log({
+      level: 'info',
+      category: 'share',
+      action: 'create_share',
+      message: '创建分享请求',
+      details: { share_type, file_path, file_name, expiry_days }
+    });
 
     if (share_type === 'file' && !file_path) {
       return res.status(400).json({
@@ -3373,25 +3377,8 @@ app.post('/api/share/:code/verify', shareRateLimitMiddleware, async (req, res) =
 
   try {
 
-    // ===== 调试日志: 分享验证开始 =====
-    console.log('[分享验证]', {
-      timestamp: new Date().toISOString(),
-      shareCode: code,
-      hasPassword: !!password,
-      requestIP: req.ip
-    });
-
     const share = ShareDB.findByCode(code);
 
-
-    // 调试日志: findByCode 结果
-    console.log('[分享验证] findByCode结果:', {
-      found: !!share,
-      expires_at: share?.expires_at || null,
-      current_time: new Date().toISOString(),
-      is_expired: share?.expires_at ? new Date(share.expires_at) <= new Date() : false
-    });
-
     if (!share) {
       return res.status(404).json({
         success: false,
@@ -3450,7 +3437,6 @@ app.post('/api/share/:code/verify', shareRateLimitMiddleware, async (req, res) =
 
       // 检查缓存
       if (shareFileCache.has(code)) {
-        console.log(`[缓存命中] 分享码: ${code}`);
         responseData.file = shareFileCache.get(code);
       } else {
         // 缓存未命中，查询存储
@@ -3461,7 +3447,6 @@ app.post('/api/share/:code/verify', shareRateLimitMiddleware, async (req, res) =
             throw new Error('分享者不存在');
           }
           const storageType = shareOwner.current_storage_type || 'oss';
-          console.log(`[缓存未命中] 分享码: ${code}，存储类型: ${storageType}`);
 
           // 使用统一存储接口
           const { StorageInterface } = require('./storage');
@@ -3552,14 +3537,6 @@ app.post('/api/share/:code/list', shareRateLimitMiddleware, async (req, res) =>
     const share = ShareDB.findByCode(code);
 
 
-    // 调试日志: findByCode 结果
-    console.log('[获取文件列表] findByCode结果:', {
-      found: !!share,
-      expires_at: share?.expires_at || null,
-      current_time: new Date().toISOString(),
-      is_expired: share?.expires_at ? new Date(share.expires_at) <= new Date() : false
-    });
-
     if (!share) {
       return res.status(404).json({
         success: false,