Vibe Usage 更新：修复 Mac 终端名称变化 + 支持 Hermes Agent

Bug Mac 终端名称变化

问题源头

macOS silently changes os.hostname() when mDNS conflicts occur (e.g.,
MacBook-Pro → MacBook-Pro-2), causing stateless re-syncs to create
duplicate device entries in the DB. Now hostname is captured once at
init and reused for all future syncs. Existing users get backfilled
on first sync after upgrade.

修复方案

在用户首次 init 或者 sync 的时候会存住这个终端的 hostname 在 config 里，之后这个终端上传就不变了

→ https://github.com/vibe-cafe/vibe-usage/commit/6d2f4b14ee6bf72e5399775b89daa375ecad50b6

Feature 支持 Hermes Agent

→ https://github.com/vibe-cafe/vibe-usage/commit/b593df9f6cdcaf10d641d70508992c253c2cfe86