[ExtraToast]

Summary

Drops observability.alertClass from the project file. deploy-kit 1.0 removed the field (JorisJonkers-dev/deploy-kit#628): once the estate composes on 1.0, a fragment that still carries it is refused, and its Project is held at its last render. The field is optional on the toolkit this repository publishes with today, so this release is valid now, and publishing it ahead of the estate's move means the move doesn't have to wait for this repository.

To know:

• On 0.31 the field reaches only the resolved artifact; no rendered object reads it, so no live object changes. 1.0 dropped it because alert rules live with the monitoring stack (feat(model): declare alert rules, the monitoring stack and receivers deploy-kit#616).
• Typed fix so release-please cuts a release, which publishes the fragment.

Testing

• With this change, every estate project file plus every Project's deploy/ on main validates on deploy-kit main: accepted (60 read).

Part of JorisJonkers-dev/deploy-kit#380.