jakekinchen TrailMates .cursorrules file for Swift

# TrailMates Profile Image Storage Rules

## Profile Image Storage Hierarchy
1. Remote Storage (Firebase)
   - profileImageUrl: Primary full-size image URL
   - profileThumbnailUrl: Optimized thumbnail URL
   - These URLs are the source of truth when available

2. Local Storage (SwiftData)
   - @Attribute(.externalStorage) profileImageData: Binary image data
   - Stored outside main database for performance
   - Used for offline access and caching

3. In-Memory (Computed)
   - profileImage: UIImage computed property
   - Provides convenient UIImage interface
   - Automatically manages conversion to/from Data

## Data Flow Rules
1. Image Upload
   - Set profileImage (converts to profileImageData)
   - Upload to Firebase
   - Clear local data
   - Store remote URLs

2. Image Download
   - Try remote URLs first (AsyncImage)
   - Fall back to local data if offline
   - Cache as needed

3. Offline Mode
   - Use profileImageData
   - Sync when online resumes

## SwiftData Integration
1. External Storage
   - Large binary data stored separately
   - Automatic cleanup by SwiftData
   - Better performance than inline storage

2. Model Requirements
   - User must be final class
   - @Model attribute required
   - Codable conformance maintained

## Validation Rules
1. Location Coordinates
   - Both latitude and longitude required if either present
   - Throws error if only one coordinate provided

2. Image Data
   - JPEG compression at 0.8 quality
   - Thumbnail generation handled by Firebase

## Equality Comparison
All properties compared including:
- Profile image data
- Remote URLs
- Location coordinates
- Optional properties