fix: 修复前端所有页面的文字溢出问题

修复内容：
1. 文件列表 - 列表视图文件名溢出控制
2. 用户列表 - 用户名和邮箱溢出控制
3. 分享列表 - 文件路径和分享链接溢出控制

所有长文本现在都会正确显示省略号，不会导致UI布局异常

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

backend/check_expire.sql

@@ -0,0 +1,19 @@
+SELECT 
+  share_code,
+  substr(share_path, 1, 30) as path,
+  created_at,
+  expires_at,
+  datetime('now') as current_time,
+  CASE 
+    WHEN expires_at IS NULL THEN '永久有效'
+    WHEN expires_at > datetime('now') THEN '未过期'
+    ELSE '已过期'
+  END as status,
+  CASE 
+    WHEN expires_at IS NOT NULL AND expires_at > datetime('now') THEN '通过'
+    WHEN expires_at IS NULL THEN '通过'
+    ELSE '拦截'
+  END as findByCode_result
+FROM shares
+ORDER BY created_at DESC
+LIMIT 10;

backend/test_expire.js

@@ -0,0 +1,27 @@
+const { ShareDB } = require('./database');
+
+// 测试过期验证
+console.log('=== 测试分享过期验证 ===\n');
+
+// 获取所有分享
+const { db } = require('./database');
+const allShares = db.prepare('SELECT share_code, created_at, expires_at, datetime("now") as current_time FROM shares LIMIT 5').all();
+
+console.log('数据库中的分享:');
+allShares.forEach(share => {
+  console.log(`\n分享码: ${share.share_code}`);
+  console.log(`创建时间: ${share.created_at}`);
+  console.log(`到期时间: ${share.expires_at || '永久'}`);
+  console.log(`当前时间: ${share.current_time}`);
+
+  if (share.expires_at) {
+    const isExpired = share.expires_at <= share.current_time;
+    console.log(`是否过期: ${isExpired ? '是' : '否'}`);
+  }
+
+  // 测试findByCode
+  const found = ShareDB.findByCode(share.share_code);
+  console.log(`findByCode结果: ${found ? '找到' : '未找到(已过滤)'}`);
+});
+
+console.log('\n=== 测试完成 ===');