[Jetty] Added the stream notifier archetype.

[moetemp]

What changed?

This PR adds the stream notifier, a CHASM execution per stream that holds its readers' callbacks.

• chasm/lib/streamnotifier keys a notifier by workflow/<id>/<first run>/<topic>, so one notifier serves the stream across a run chain.
• Attach is idempotent and capped by streamnotifier.maxCallbacks. Notify keeps the highest counter and hands it to every callback as progress. Close completes them all.
• A closed notifier answers late attaches for streamnotifier.closedRetention (7 days).
• The first-run check at attach takes the first run of any chain of the Workflow id. So a reader of an earlier chain still attaches after the id was reused.
• An owner check every streamnotifier.ownerCheckInterval closes the stream when the owner chain ended, after streamnotifier.ownerCloseGrace.
• It's behind streamnotifier.enabled, off by default.

It carries moetemp/temporal#41. Attach still keeps the operation token and start time (DD-70). A Nexus callback takes only the completion here, since its progress delivery stays in Bridge.

Why?

A notifier keyed by the stream survives worker restarts and works for every producer kind (DD-31). An owner that ended closes the stream (DD-73, DD-108).

How did you test it?

Link to a test plan if any -

• Unit Tests
• Staging
• End to End Tests

Unit tests in chasm/lib/streamnotifier, and the functional TestStreamNotifier* tests on CHASM and HSM callers.