Don't block on global scope during ext startup

[eleanorjboyd]

When at least one workspace folder resolved successfully, don't await the global scope resolution. Run it as a background task instead of blocking startup on it.

For more than 3/4ths of slow sessions where the workspace env resolves fast (via envPreResolved), this should make the status bar update near-instantly.

Files opened outside the workspace folder wouldn't have a Python env immediately available. They would resolve moments later when the background task completes.

[Copilot]

Pull request overview

Note

Copilot was unable to run its full agentic suite in this review.

This PR optimizes extension startup by avoiding blocking on global-scope environment resolution when at least one workspace folder environment has already been resolved, deferring the global resolution to a background task.

Changes:

• Defer global-scope environment selection to a background task when a workspace environment is available.
• Add telemetry for “blocking time” of initial environment selection, including whether global scope was deferred.
• Expand unit tests to cover error handling, deferral behavior, and additional settings-error warning paths.

Show a summary per file

File	Description
src/features/interpreterSelection.ts	Defers global env resolution when a workspace env is resolved; adds completion telemetry and error-handling adjustments.
src/common/telemetry/constants.ts	Introduces a new telemetry event name + GDPR property mapping for env selection completion.
src/test/features/interpreterSelection.unit.test.ts	Adds tests for new deferral behavior and error/warning paths in environment selection.

Copilot's findings

• Files reviewed: 3/3 changed files
• Comments generated: 4