Auto-set FSharpCompilerPath when debugging VisualFSharpDebug VSIX (#19083)

Author: Copilot

vsintegration/Vsix/Directory.Build.props

@@ -6,6 +6,8 @@
     <VisualStudioInsertionComponent>Microsoft.FSharp</VisualStudioInsertionComponent>
     <VSRootSuffix>RoslynDev</VSRootSuffix>
     <VSSDKTargetPlatformRegRootSuffix>$(VSRootSuffix)</VSSDKTargetPlatformRegRootSuffix>
+    <!-- Path to the locally built F# compiler for use during VSIX debugging -->
+    <FSharpCompilerPathForDebuggingLocally>$(ArtifactsDir)bin\fscAnyCpu\$(Configuration)\net472\</FSharpCompilerPathForDebuggingLocally>
     <CreateVsixContainer>true</CreateVsixContainer>
     <PublishUrl>publish\</PublishUrl>
     <Install>true</Install>

vsintegration/Vsix/VisualFSharpFull/Properties/launchSettings.json

@@ -3,7 +3,16 @@
     "VisualFSharpDebug": {
       "commandName": "Executable",
       "executablePath": "$(DevEnvDir)devenv.exe",
-      "commandLineArgs": "/rootsuffix $(VSSDKTargetPlatformRegRootSuffix) /log"
+      "commandLineArgs": "/rootsuffix $(VSSDKTargetPlatformRegRootSuffix) /log",
+      "environmentVariables": {
+        "FSharpCompilerPath": "$(FSharpCompilerPathForDebuggingLocally)",
+        "DisableAutoSetFscCompilerPath": "true",
+        "FSharpPreferNetFrameworkTools": "true",
+        "FSharp_Shim_Present": "true",
+        "FSharpPreferAnyCpuTools": "true",
+        "Fsc_NetFramework_ToolPath": "$(FSharpCompilerPathForDebuggingLocally)",
+        "Fsc_NetFramework_AnyCpu_ToolExe": "fscAnyCpu.exe"
+      }
     }
   }
 }