feat: implement operator explanation layer (#191)
## Summary
- add the shared operator explanation layer with explanation families, trustworthiness semantics, count descriptors, and centralized badge mappings
- adopt explanation-first rendering across baseline compare, governance operation run detail, baseline snapshot presentation, tenant review detail, and review register rows
- extend reason translation, artifact-truth presentation, fallback ops UX messaging, and focused regression coverage for operator explanation semantics
## Testing
- vendor/bin/sail bin pint --dirty --format agent
- vendor/bin/sail artisan test --compact tests/Feature/Monitoring/OperationsTenantScopeTest.php tests/Feature/Operations/OperationRunBlockedExecutionPresentationTest.php
- vendor/bin/sail artisan test --compact
## Notes
- Livewire v4 compatible
- panel provider registration remains in bootstrap/providers.php
- no destructive Filament actions were added or changed in this PR
- no new global-search behavior was introduced in this slice
Co-authored-by: Ahmed Darrazi <ahmed.darrazi@live.de>
Reviewed-on: #191