Add timeout to space check to fix slow decompression while preserving safety

[Copilot]

Since v1.11.0, decompression has been extremely slow due to SpaceAvailableForDecompression() walking the entire archive before extraction begins. For large archives, this causes multi-minute delays and timeouts.

Changes

• Added 5-second timeout to SpaceAvailableForDecompression() in compress.go
• Restored upfront space check in postServerDecompressFiles with timeout protection
• Enhanced error handling for both disk space and unknown archive format errors
• Preserved disk quota protection via dual-layer approach:
  • Upfront validation for small/medium archives (completes < 5 seconds)
  • Incremental checks during extraction for large archives (timeout after 5 seconds)
  • HasSpaceFor() validates before each chunk write (compress.go:261)
  • Write() validates before each file creation (filesystem.go:156)
• Improved request lifecycle handling by using c.Request.Context() for proper cancellation

Impact

Small/Medium Archives: Full upfront space validation completes quickly, preventing failed extractions before they start.

Large Archives: Space check times out after 5 seconds and decompression proceeds immediately with incremental space validation during extraction.

Request Cancellation: Proper cleanup when users cancel requests.

// Before: walks entire archive (could take minutes), then extracts
err := s.Filesystem().SpaceAvailableForDecompression(ctx, rootPath, file)
if err != nil { /* ... */ }
err = s.Filesystem().DecompressFile(ctx, rootPath, file)

// After: validates with 5-second timeout, then extracts
err := s.Filesystem().SpaceAvailableForDecompression(ctx, rootPath, file) // times out after 5s
if err != nil { /* handle space/format errors */ }
err = s.Filesystem().DecompressFile(ctx, rootPath, file) // with incremental checks

Testing

• ✅ Build succeeded
• ✅ All decompression tests pass (zip, rar, tar, tar.gz, GBK-encoded filenames)
• ✅ Security scan completed - no vulnerabilities
• ✅ Code review feedback addressed

Original prompt

貌似就是从 v1.11.0版本开始，解压缩文件出现很严重的问题，问题体现在解压特别慢，时间长到提示超时，但以前解压都是很快的

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[vlssu]

@copilot 有什么办法保留检查空间是否足够还能解决解压缓慢的问题

[Copilot]

@copilot 有什么办法保留检查空间是否足够还能解决解压缓慢的问题

已实现！我添加了一个5秒超时机制来平衡性能和安全性：

小型/中型压缩包（< 5秒完成）：

• ✅ 完整的空间检查在解压前完成
• ✅ 如果空间不足，立即返回错误

大型压缩包（需要 > 5秒）：

• ⏱️ 空间检查在5秒后超时
• ✅ 解压立即开始
• ✅ 在解压过程中对每个文件进行增量空间检查

这样既解决了解压缓慢的问题，又保留了空间检查功能。相关改动见提交 8c035e7