# 03. Implement iOS data models (Swift)

meta:
  id: native-business-logic-migration-03
  feature: native-business-logic-migration
  priority: P0
  depends_on: [native-business-logic-migration-02]
  tags: [implementation, ios, data-models]

objective:
- Implement all data models in Swift following iOS conventions

deliverables:
- FeedItem.swift
- Feed.swift
- FeedSubscription.swift
- SearchResult.swift
- SearchFilters.swift
- NotificationPreferences.swift
- ReadingPreferences.swift
- Supporting types and extensions

tests:
- Unit: Test property encoding/decoding
- Unit: Test custom string interpolation
- Unit: Test equality conformance

acceptance_criteria:
- All models conform to Codable
- All models have proper equatable conformance
- Date properties use ISO8601 formatter
- Optional properties properly handled
- Custom debug description implemented

validation:
- Run `swift test` in Xcode
- Verify compilation with no warnings

notes:
- Use Swift 5.9+ features
- Follow Apple's API design guidelines
- Consider using Identifiable protocol for List conformance
