[untra]

Brings changes from coder/coder-desktop-windows over to Linux, so both repos build with the same dotnet10 toolchain. That's a first step toward combining the builds.

• Decompression fix (#185): the Downloader HttpClient now only accepts gzip and deflate (it used to be DecompressionMethods.All), the same as Windows.
• .NET 10 (#189): every project targets net10.0. global.json pins SDK 10.0.100 with latestFeature, CI and release use 10.0.x, and the deb, rpm, and PKGBUILD packages now depend on dotnet-runtime-10.0 / dotnet-sdk-10.0. I bumped Microsoft.Extensions.* to 10.0.14, the test packages to the Windows versions, and LangVersion from 12 to 14.0. System.IO.Pipelines is removed because it's in-box now. The EV cert test uses X509CertificateLoader instead of the obsolete X509Certificate2 constructor.
• LF line endings (#189): .editorconfig now uses end_of_line = lf, and .gitattributes has * text=auto eol=lf. That renormalizes AGENTS.md and Coder.Desktop.sln.
• Minor adjustment to linux tray icon display

Release packages are framework-dependent, so installing them now requires the .NET 10 runtime from the distro or the Microsoft package feed.

Validated locally with SDK 10.0.404: tested on arm64 ubuntu 26.04