VS Code: populate thread inputs from default/sample conversation

[sethjuarez]

Summary

When running a .prompty file from the VS Code extension, thread inputs should be pre-populated from the prompt's declared default/sample conversation when one exists.

Scenario

A prompt can declare a conversation history input using kind: thread:

inputs:
  - name: conversation
    kind: thread
    description: Prior user/assistant turns.
    default:
      - role: user
        content: I care most about safety and want to inspect the north pipeline first.
      - role: assistant
        content: I will prioritize the north pipeline and keep safety constraints visible.
  - name: currentRequest
    kind: string
    default: The storm shifted east. Should we still use the previous route?

The body then places the thread before the current user turn:

system:
You are a mission assistant.

{{ conversation }}

user:
{{ currentRequest }}

Expected behavior

When executing the prompt from VS Code, the extension should bring the default/sample thread messages into the run input so the prepared messages include:

1. the system message,
2. the prior user/assistant turns from the thread input,
3. the current user request.

Actual behavior

The threaded execution path appears not to load the sample/default conversation, so the run does not reflect the intended multi-turn context unless the user manually supplies it.

Why it matters

Thread inputs are the recommended way to demonstrate and test multi-turn behavior. If VS Code execution ignores the provided default/sample thread, authors cannot easily verify conversation-history prompts directly from the editor.