feat: Implement photo performance optimization and introduce new photo management features

- Added a comprehensive document detailing performance optimizations for the photo grid, addressing issues with loading and caching.
- Introduced `PhotoThumbnailCache` for efficient thumbnail management, leveraging `PHCachingImageManager` and `NSCache`.
- Updated `PhotoManager2` to utilize a singleton pattern for shared access and improved photo loading strategies.
- Enhanced `PhotosViewModel` and `PhotosView` to support pagination and optimized thumbnail loading for smoother user experience.
- Created new views and components for managing photo backups and displaying photo details, including a job monitor for background tasks.
- Refactored existing code to improve structure and maintainability, ensuring better performance with large photo libraries.

packages/swift-client/Sources/SpacedriveClient/SpacedriveClient.swift

@@ -163,7 +163,10 @@ public class SpacedriveClient {
             // Encode input to JSON for non-unit types
             let requestData: Data
             do {
-                requestData = try JSONEncoder().encode(requestPayload)
+                let encoder = JSONEncoder()
+                // Don't omit nil values - we need them to be present as null
+                // This is handled by the Codable implementation of the structs
+                requestData = try encoder.encode(requestPayload)
             } catch {
                 throw SpacedriveError.serializationError("Failed to encode request: \(error)")
             }