Connect worker_boot failure classification to recovery_recipes policy:
- Add FailureScenario::ProviderFailure variant
- Add FailureScenario::from_worker_failure_kind() bridge function
mapping every WorkerFailureKind to a concrete FailureScenario
- Add RecoveryStep::RestartWorker for provider failure recovery
- Add recipe for ProviderFailure: RestartWorker -> AlertHuman escalation
- 3 new tests: bridge mapping, recipe structure, recovery attempt cycle
Previously a claw that detected WorkerFailureKind::Provider had no
machine-readable path to 'what should I do about this?'. Now it can
call from_worker_failure_kind() -> recipe_for() -> attempt_recovery()
as a single structured chain.
Closes the silo between worker_boot and recovery_recipes.