Baixar Antigravity Tools 4.9.0 per a Windows

- [Monitor Logging & Thought-Signature Backfill Hardening] Fix Tokio Worker Panic and Connection Hang Caused by Byte-Slicing Thought Snippets on Multi-Byte Character Boundaries (PR #3574, Fixes #3573, Thanks to @a3339530357):
- Safe UTF-8 Character Boundary Truncation: Fixed a standard library char boundary panic in monitor.rs's thought signature backfill path, where raw byte-slicing &trimmed[..32] was executed on thinking content. When multi-byte characters (e.g. Chinese at 3 bytes/char or Emojis at 4 bytes) straddled the 32nd byte index, slicing inside a code point caused immediate panics. Replaced with the existing shared utility safe_truncate_str(trimmed, 32), which automatically rolls back to the nearest valid character boundary.
- Eradicate Downstream Connection Drops & Silent Log Losses: Permanently eliminated Tokio worker crashes triggered by this panic, resolving socket hang up / Empty reply from server errors in downstream clients (such as Chinese coding agents and chatbots) during non-streaming requests, and ensuring monitor request logs are 100% reliably persisted to the database.

- [监控日志与思考签名回填安全加固] 修复思考片段按字节切片切在多字节字符中间导致的 Rust worker panic 与连接挂起 (PR #3574, Fixes #3573, Thanks to @a3339530357):
- UTF-8 字符边界安全回退：修复在 monitor.rs 签名回填路径中对思考内容执行 &trimmed[..32] 原生字节切片时，因中文（3 字节/字）或 Emoji（4 字节）等宽字符横跨第 32 字节触发的标准库 char boundary panic。改用通用工具 safe_truncate_str(trimmed, 32)，在截断点落在多字节内部时自动向左回退至最近合法字符边界。
- 根治下游连接中断与日志静默丢失：彻底消除由上述 panic 引发的 tokio worker 崩溃，解决下游应用（如中文 Agent、聊天客户端）在非流式模式下收到的 socket hang up / Empty reply from server 异常，确保请求监控日志 100% 完整落库。
What's Changed
- fix(monitor): 修复思考片段按字节截断切在多字节字符中间导致的连接 panic by @a3339530357 in https://github.com/lbjlaq/Antigravity-Manager/pull/3574
New Contributors
- @a3339530357 made their first contribution in https://github.com/lbjlaq/Antigravity-Manager/pull/3574
Full Changelog: https://github.com/lbjlaq/Antigravity-Manager/compare/v4.8.9...v4.9.0