Fix Open Terminal

[todi1856]

This PR fixes two issues:

Windows: no terminal window opened on CoreCLR

How it broke
OpenTerminal started cmd.exe with new ProcessStartInfo("cmd.exe") { WorkingDirectory = ... } and left UseShellExecute at its default. The default is different on each runtime:

• Mono / .NET Framework: UseShellExecute defaults to true. The process goes through ShellExecuteEx, which gives cmd.exe its own console window.
• CoreCLR (.NET): UseShellExecute defaults to false. The process is started directly through CreateProcess and inherits the Editor's standard handles. The Editor is a GUI app and has no usable console, so cmd.exe gets no interactive console and no terminal window shows up.

Fix
Set UseShellExecute = true explicitly. This brings back the old Mono behaviour on both runtimes.

Linux: OpenTerminal was not implemented

OpenTerminal had no RuntimePlatform.LinuxEditor case, so on Linux it fell through to default and threw Don't know how to open terminal on LinuxEditor.

Claude provided default implementation so this works now just fine

2026-09-25.16-49-46.mp4

[u-pr]

💡 Harness Review

The change adds Linux terminal launching and adjusts Windows launching, but the Linux path mishandles some valid launcher settings and SDK directory names.

_{Reviewed commit c7443a9}

_{🤖 Helpful? 👍/👎}

[todi1856]

/review

[u-pr]

💡 Harness Review

The change adds Linux terminal support and updates Windows launching, with one reachable failure in the Linux terminal selection path.

_{Reviewed commit 7b60fdd}

_{🤖 Helpful? 👍/👎}

[IGuscin]

Tomas verified that open terminal works properly, both on Win and Linux