perf: concurrent quota refresh for all accounts

[Mag1cFall]

Changes

Refactored refresh_all_quotas command from sequential to concurrent execution using futures::future::join_all.

• Used futures::future::join_all to spawn concurrent async tasks
• Each account's quota fetch and save operations run in parallel
• Preserved original filtering logic (skip disabled/forbidden accounts)
• Preserved error handling and logging per account

Safety Analysis

The original code had a comment: // 串行处理以确保持久化安全 (SQLite)

This comment is legacy/outdated. Current storage implementation:

// save_account function
let account_path = accounts_dir.join(format!("{}.json", account.id));
fs::write(&account_path, content)

Each account is stored in a separate JSON file ({account_id}.json), not SQLite. Concurrent writes to different files are completely safe - no race conditions or data corruption possible.

[lbjlaq]

感谢您的贡献！🎉

此 PR 的更改已被手动集成到 v3.3.16 版本中。

相关更新已包含在以下文件中：

• README.md 的版本更新日志
• 贡献者列表

再次感谢您对 Antigravity Tools 项目的支持！

---

Thank you for your contribution! 🎉

The changes from this PR have been manually integrated into v3.3.16.

The updates are documented in:

• README.md changelog
• Contributors list

Thank you again for your support of the Antigravity Tools project!

[lbjlaq]

已集成到 v3.3.16，关闭此 PR。