Modifying Subscriptions (subscriptions/modify)

[leogdion]

[leogdion]

Status Update: The modifySubscriptions operation exists in Sources/MistKit/Generated/Client.swift (line 2237) but is not exposed in the public CloudKitService API.

What needs to be done:

1. Create public wrapper methods in CloudKitService+Operations.swift:
   • createSubscription(_:)
   • deleteSubscription(_:)
   • modifySubscriptions(_:) for batch operations
2. Define subscription types (query, zone, database)
3. Add comprehensive documentation with APNs integration examples
4. Add tests for create/delete/modify subscription scenarios

Generated operation signature:

internal func modifySubscriptions(_ input: Operations.modifySubscriptions.Input) 
  async throws -> Operations.modifySubscriptions.Output

Part of the subscriptions API (#49, #50, #51) - essential for CloudKit push notifications.