Extend reconciliation sweep to re-derive and re-emit missed kernel transitions

Extend the reconciliation sweep (SyncContainerLifecyclesTask) to re-derive kernel transitions from actual container state and re-emit transitions the Manager may have missed; the Manager applies idempotently via from_status (BEP-1061 section 3g/3f). No heartbeat digest.

On Agent restart the local phase is reconstructed from kernel_registry container labels (pickle excluded); the restart itself emits no events and does not touch history.

Note: coordinate with BEP-1057 restart recovery (BA-6765) to avoid duplicated recovery logic - define the recovery(mechanism) vs reporting(this) seam.

Success Criteria:
- [ ] Sweep re-derives transitions from actual container state and re-emits missed ones
- [ ] Re-emission is safe via from_status-based idempotent apply
- [ ] Local phase reconstructed from container labels (no pickle)
- [ ] pants test passes for affected packages

JIRA Issue: BA-6855

Start by locating SyncContainerLifecyclesTask and reading the referenced BEP-1061 sections, then review BEP-1057 restart recovery (BA-6765) and the kernel_registry label handling. Verify how actual container state is available and define the recovery-versus-reporting seam. Done means missed transitions are re-emitted idempotently, restart reconstruction uses labels without pickle or history changes, and affected pants tests pass.

Written by the indexing model from the issue text.