Applied the decision-first global surface IA contract to BackupSet views. Includes decision summary header, usability status, and separation of technical metadata.
## Summary
- harden nested Filament and Livewire tenant-context handling across the backup schedule operation runs relation manager, managed-environment triage arrival continuity, the backup set policy picker table, and the Operate Hub shell
- add architecture, feature, and browser coverage for nested Filament tenant-context continuity and restore-run resource behavior
- add the Spec 334 artifacts (`spec.md`, `plan.md`, `tasks.md`, and the requirements checklist)
## Testing
- Not run as part of this commit/push/PR workflow
Co-authored-by: Ahmed Darrazi <ahmed.darrazi@live.de>
Reviewed-on: #395
