Create CoreDataItemRepository

[DrunkOnJava]

📋 Sub-task of #86

Description

Replace the in-memory DefaultItemRepository with a Core Data backed implementation.

Current Implementation

• DefaultItemRepository.swift uses DispatchQueue and array storage
• All data is lost on app restart

Implementation Tasks

• Create CoreDataItemRepository conforming to ItemRepository protocol
• Implement all CRUD operations using Core Data
• Add batch operations for performance
• Implement fuzzy search using Core Data predicates
• Add proper error handling and recovery
• Optimize fetch requests with proper indexes

Key Methods to Implement

• fetchAll() - with pagination support
• fetch(id:) - optimized single item fetch
• save(_:) - with conflict resolution
• delete(_:) - with cascade handling
• search(query:) - full text search
• fetchByCategory(_:) - filtered queries
• fetchByLocation(_:) - relationship queries

Performance Requirements

• Fetch 10,000 items < 100ms
• Save batch of 100 items < 500ms
• Search response < 50ms

Migration Path

• Create parallel implementation
• Add feature flag for gradual rollout
• Implement data migration from existing storage
• Deprecate DefaultItemRepository

Testing Requirements

• Unit tests for all CRUD operations
• Performance tests with large datasets
• Concurrent access tests
• Error recovery tests

Estimated Effort: 3-4 days

[DrunkOnJava]

Closing: This issue has been resolved/superseded by the complete modular architecture restructure now in main branch (commit 33a0ead). The new architecture implements a comprehensive solution that addresses the core needs this issue was tracking.