[do not review] Fix stale AppHost running state after debug session ends

[ellahathaway]

Summary

The VS Code Aspire extension kept showing an AppHost as "running" in its tree view after the user stopped an F5 debug session.

Root cause

aspire ps --follow reports a stopped event only as an incremental delta. When a debug session ends the AppHost is hard-killed, so the live follow stream never emits its stopped delta and keeps reporting the AppHost as running. A fresh one-shot aspire ps snapshot is authoritative (the AppHost is gone), but nothing triggered one on debug stop.

Fix

• Seed the global ps polling with an authoritative one-shot aspire ps snapshot, then attach the --follow stream, so the repository reconciles to ground truth on every (re)start.
• Route debug-stop through the existing stopping lifecycle: on debug-session end the AppHost is marked stopping (spinner) and the ps stream is restarted, replacing the stale follow with a fresh authoritative snapshot that reconciles the stopped AppHost out of the tree.
• Reduce tree re-render churn by restarting only the ps stream on debug stop instead of doing a full workspace rediscovery.

Testing

• yarn run compile-tests, yarn run compile, yarn run lint all green.
• Unit test updates for the seed-then-follow reordering are still in progress.

Draft while remaining unit test work is finished.

[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/microsoft/aspire/main/eng/scripts/get-aspire-cli-pr.sh | bash -s -- 17965

Or

• Run remotely in PowerShell:

iex "& { $(irm https://raw.githubusercontent.com/microsoft/aspire/main/eng/scripts/get-aspire-cli-pr.ps1) } 17965"

[adamint]

ensure there is an e2e test here @ellahathaway - have an agent check it fails before the fix