ObjectDisposedException from StopAllAsync when a second Pause/Stop fans out over disposed daemons (marten#5055)

[jeremydmiller]

Upstream report: JasperFx/marten#5055

At Kubernetes pod shutdown, users see repeated Error while trying to stop daemon agents logs:

System.ObjectDisposedException: The CancellationTokenSource has been disposed.
   at System.Threading.CancellationTokenSource.get_Token()
   at JasperFx.Events.Daemon.JasperFxAsyncDaemon`3.StopAllAsync()
   at JasperFx.Events.Daemon.ProjectionCoordinatorBase.PauseAsync()

Root cause

• JasperFxAsyncDaemon.StopAllAsync() begins with await _semaphore.WaitAsync(_cancellation.Token). If Dispose() already ran (_cancellation?.Dispose()), reading .Token throws ObjectDisposedException.
• ProjectionCoordinatorBase.StopAsync() calls PauseAsync() then daemon.SafeDispose() on every resolved daemon, but the subclass daemon caches (e.g. Marten's ProjectionCoordinator._daemons) are never cleared. Any second Pause/Stop — double AddAsyncDaemon hosted-service registration, user pause + host stop, Wolverine quiesce + host stop — fans StopAllAsync() out over disposed daemons, and PauseAsync() logs each one at Error level.
• Latent second bug: after StopAsync, ResumeAsync and the daemon accessors hand back disposed daemons from the stale cache.

Fix

1. JasperFxAsyncDaemon: _disposed flag, idempotent Dispose(), StopAllAsync() no-ops when disposed (including the Dispose-races-an-in-flight-stop window).
2. ProjectionCoordinatorBase.PauseAsync: catch ObjectDisposedException and log at Debug — same philosophy as the ProjectionCoordinatorBase.executeAsync: terminate on cancellation / disposed data source instead of re-polling (shutdown drain race) #499/#499: terminate coordinator loop on disposed data source / wrapped cancellation #500 handling in executeAsync.
3. ProjectionCoordinatorBase.StopAsync: new ClearResolvedDaemons() seam so subclass caches are purged after disposal; ResumeAsync then rebuilds fresh daemons.

Marten/Polecat need to implement the new seam when they bump (Marten side also wants AddAsyncDaemon idempotence — tracked separately on marten#5055).