Publish to OpenVSX

[matifali]

To support non-MS VScode versions, like Cursor and WindSurf IDE, that can not access the VSCode marketplace, investigate if we can publish to OpenVSX Registry. Coder depends on Remote Development, which is also exclusively available in VSCode marketplace.

[code-asher]

Supposedly Cursor uses anysphere.open-remote-ssh but that is not available in Open VSX either. I wonder if this one works instead: https://open-vsx.org/extension/jeanp413/open-remote-ssh

Or maybe anysphere.open-remote-ssh is included in the base distribution of Cursor? If so we could just remove the dependency, but then it would not work with VSCodium for example.

[matifali]

Supposedly Cursor uses anysphere.open-remote-ssh but that is not available in Open VSX either.

According to my recent observation, Crsor somehow downloads the MS vscode remote extension when we first try to connect to an SSH host. This makes Coder work with Cursor but not other VSCodium-based IDEs that can't install the MS vscode remote extension.

Probably Cursor has its implementation.

[matifali]

Closing in favor of #408