[4i7]

Fixes the remaining pre-publication exit race exposed by AppInfo lifetime regressions B/J.

The process can become exited after EnableRaisingEvents succeeds while the Exited event is still pending. The previous arbitration path only checked ExitObserved before publishing when no winner existed, so an already-exited candidate could briefly be returned as Watching.

Changes:

• run GetUnpublishedCandidateState(data) at the start of every publication-arbitration iteration
• return AlreadyExited for a definite exited candidate and Unavailable for an unverifiable candidate before publication
• preserve the existing ExitObserved lock recheck, winner generation validation, and exact winner transfer checks
• apply the identical runtime implementation in tools/Optimize-MyMix/15-process-watcher-lifecycle.ps1
• leave Test-AppInfoCacheLifetime.ps1 unchanged; B/J remain the regression gate for this behavior

This keeps the intended invariant: an unpublished candidate must be validated as Current before it can become the published watcher.