Linux: process-group kill and full command names from ps

dotnet watch is spawned detached on Unix so stop() can signal the whole
group; ps output uses args instead of the 15-character comm field.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_0169iPWwKHZoBTNN9qwXiwqk

README.md

@@ -250,6 +250,15 @@ honoured, so both extensions use the same SDK.
   terminal and the *Problems* panel (`$msCompile`).
 - The *.NET Solution* output channel logs every `dotnet` invocation.
 
+## Platforms
+
+Windows, Linux and macOS. The only platform-specific code is around processes: the
+apphost is `MyGame.Editor.exe` on Windows and `MyGame.Editor` elsewhere; the process
+list comes from `wmic` (or PowerShell's CIM query where wmic is gone) on Windows and
+`ps -eo pid,ppid,args` elsewhere; and stopping hot reload uses `taskkill /T` on Windows
+and a process-group signal on Unix, where `dotnet watch` is started detached for that
+reason.
+
 ## Development
 
 ```