[Feature] Log effective Windows shell for local runtime observability

[wcqqq1214]

Feature Description

When the Local runtime resolves the Windows shell (pwsh.exe vs powershell.exe), log which one is actually used, so users can diagnose environment issues like PATH differences, pwsh not detected, or unexpected fallback.

Suggested by C10H14N2O5 in #9622.

Use Case

No response

Checklist

• I have searched the Issue list for related features and confirmed this feature idea has never been proposed.
• The feature I am suggesting is related to AstrBot itself, not to a specific plugin.
• I have read and agree to the project's Code of Conduct.
• (Optional) I am willing to submit a PR to help implement this feature.

[C10H14N2O5]

Hi @wcqqq1214, I'm interested in trying to implement this as my first contribution to AstrBot. Are you already working on a PR for this issue? If not, I'd be happy to take a look at it ;).

[wcqqq1214]

Hi @C10H14N2O5, No, I'm not working on it — please go ahead, I'd be glad to have you take this one.