feat: comprehensive metadata namespace architecture and cleanup system

BREAKING CHANGE: Remove hard delete option from deleteVerb() for consistent API

- Add complete metadata namespace architecture with O(1) soft delete performance
- Implement periodic cleanup system for old soft-deleted items
- Add restore methods for both nouns and verbs
- Require metadata contracts for all augmentations
- Eliminate namespace collisions with clean separation (_brainy, _augmentations, _audit)
- Optimize index performance using flattened dot-notation for O(1) lookups
- Add comprehensive augmentation safety system with type-safe access control
- Maintain full backward compatibility for existing data
- Add enterprise-grade cleanup with configurable age thresholds and batch processing

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

src/augmentations/requestDeduplicatorAugmentation.ts

@@ -22,6 +22,7 @@ interface DeduplicatorConfig {
 export class RequestDeduplicatorAugmentation extends BaseAugmentation {
   name = 'RequestDeduplicator'
   timing = 'around' as const
+  metadata = 'none' as const  // Doesn't access metadata
   operations = ['search', 'searchText', 'searchByNounTypes', 'findSimilar', 'get'] as ('search' | 'searchText' | 'searchByNounTypes' | 'findSimilar' | 'get')[]
   priority = 50 // Performance optimization