vs code extension file-based app fixes

[adamint]

Description

Discovered during dogfooding. File-based apps should be built before launch, as we aren't using dotnet run to launch them (which will handle build). Also, for polyglot apphosts, to debug file-based apps we need KnownConfigNames.DebugSessionRunMode to be respected (NoDebug is currently set based on whether a debugger is attached, which is not true for the apphost server).

Removes C# dev kit build of dotnet projects and just uses the dotnet CLI. We had agreed to make this change before, it just never happened.

Fixes #15161 and fixes #15162

Checklist

• Is this feature complete?
  • Yes. Ready to ship.
  • No. Follow-up changes expected.
• Are you including unit tests for the changes and scenario tests if relevant?
  • Yes
  • No
• Did you add public API?
  • Yes
    • If yes, did you have an API Review for it?
      • Yes
      • No
    • Did you add <remarks /> and <code /> elements on your triple slash comments?
      • Yes
      • No
  • No
• Does the change make any security assumptions or guarantees?
  • Yes
    • If yes, have you done a threat model and had a security review?
      • Yes
      • No
  • No
• Does the change require an update in our Aspire docs?
  • Yes
    • Link to aspire.dev issue:
      • New issue
  • No

[github-actions]

🚀 Dogfood this PR with:

⚠️ WARNING: Do not do this without first carefully reviewing the code of this PR to satisfy yourself it is safe.

curl -fsSL https://raw.githubusercontent.com/dotnet/aspire/main/eng/scripts/get-aspire-cli-pr.sh | bash -s -- 15170

Or

• Run remotely in PowerShell:

iex "& { $(irm https://raw.githubusercontent.com/dotnet/aspire/main/eng/scripts/get-aspire-cli-pr.ps1) } 15170"

[Copilot]

Pull request overview

Ensures file-based .NET apps are built before launch and that debug/no-debug run mode is correctly propagated for project resources (especially in polyglot AppHost scenarios), while standardizing project builds in the VS Code extension on the dotnet CLI instead of C# Dev Kit tasks.

Changes:

• Respect KnownConfigNames.DebugSessionRunMode when creating project launch configurations in the AppHost DCP executor.
• Remove C# Dev Kit task-based project builds in the extension and rely on dotnet build.
• Always build file-based apps before launching/debugging to avoid running stale cached outputs.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

File	Description
src/Aspire.Hosting/Dcp/DcpExecutor.cs	Uses configured debug session run mode for project launch configurations instead of relying solely on Debugger.IsAttached.
extension/src/debugger/languages/dotnet.ts	Removes Dev Kit build path and forces a CLI build for file-based apps before debug launch.

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[IEvangelist]

LGTM. Have you tested this with all variations of C# DevKit extension, C# extension, etc.? Just to verify it works regardless of developer setup?

[adamint]

LGTM. Have you tested this with all variations of C# DevKit extension, C# extension, etc.? Just to verify it works regardless of developer setup?

Yes! I have