Fixed a number of sync issues I noticed

ios/Ascently/Models/BackupFormat.swift

@@ -20,7 +20,6 @@ struct ClimbDataBackup: Codable {
     let problems: [BackupProblem]
     let sessions: [BackupClimbSession]
     let attempts: [BackupAttempt]
-    let deletedItems: [DeletedItem]
 
     init(
         exportedAt: String,
@@ -29,8 +28,7 @@ struct ClimbDataBackup: Codable {
         gyms: [BackupGym],
         problems: [BackupProblem],
         sessions: [BackupClimbSession],
-        attempts: [BackupAttempt],
-        deletedItems: [DeletedItem] = []
+        attempts: [BackupAttempt]
     ) {
         self.exportedAt = exportedAt
         self.version = version
@@ -39,7 +37,6 @@ struct ClimbDataBackup: Codable {
         self.problems = problems
         self.sessions = sessions
         self.attempts = attempts
-        self.deletedItems = deletedItems
     }
 }
 
@@ -52,6 +49,7 @@ struct BackupGym: Codable {
     let difficultySystems: [DifficultySystem]
     let customDifficultyGrades: [String]
     let notes: String?
+    let isDeleted: Bool?
     let createdAt: String
     let updatedAt: String
 
@@ -64,6 +62,8 @@ struct BackupGym: Codable {
         self.customDifficultyGrades = gym.customDifficultyGrades
         self.notes = gym.notes
 
+        self.isDeleted = false // Default to false until model is updated
+
         let formatter = ISO8601DateFormatter()
         formatter.formatOptions = [.withInternetDateTime, .withFractionalSeconds]
         self.createdAt = formatter.string(from: gym.createdAt)
@@ -78,6 +78,7 @@ struct BackupGym: Codable {
         difficultySystems: [DifficultySystem],
         customDifficultyGrades: [String] = [],
         notes: String?,
+        isDeleted: Bool = false,
         createdAt: String,
         updatedAt: String
     ) {
@@ -88,6 +89,7 @@ struct BackupGym: Codable {
         self.difficultySystems = difficultySystems
         self.customDifficultyGrades = customDifficultyGrades
         self.notes = notes
+        self.isDeleted = isDeleted
         self.createdAt = createdAt
         self.updatedAt = updatedAt
     }
@@ -115,6 +117,25 @@ struct BackupGym: Codable {
             updatedAt: updatedDate
         )
     }
+
+    static func createTombstone(id: String, deletedAt: Date) -> BackupGym {
+        let formatter = ISO8601DateFormatter()
+        formatter.formatOptions = [.withInternetDateTime, .withFractionalSeconds]
+        let dateString = formatter.string(from: deletedAt)
+
+        return BackupGym(
+            id: id,
+            name: "DELETED",
+            location: nil,
+            supportedClimbTypes: [],
+            difficultySystems: [],
+            customDifficultyGrades: [],
+            notes: nil,
+            isDeleted: true,
+            createdAt: dateString,
+            updatedAt: dateString
+        )
+    }
 }
 
 // Platform-neutral problem representation for backup/restore
@@ -131,6 +152,7 @@ struct BackupProblem: Codable {
     let isActive: Bool
     let dateSet: String?  // ISO 8601 format
     let notes: String?
+    let isDeleted: Bool?
     let createdAt: String
     let updatedAt: String
 
@@ -146,6 +168,7 @@ struct BackupProblem: Codable {
         self.imagePaths = problem.imagePaths.isEmpty ? nil : problem.imagePaths
         self.isActive = problem.isActive
         self.notes = problem.notes
+        self.isDeleted = false // Default to false until model is updated
 
         let formatter = ISO8601DateFormatter()
         formatter.formatOptions = [.withInternetDateTime, .withFractionalSeconds]
@@ -167,6 +190,7 @@ struct BackupProblem: Codable {
         isActive: Bool,
         dateSet: String?,
         notes: String?,
+        isDeleted: Bool = false,
         createdAt: String,
         updatedAt: String
     ) {
@@ -182,6 +206,7 @@ struct BackupProblem: Codable {
         self.isActive = isActive
         self.dateSet = dateSet
         self.notes = notes
+        self.isDeleted = isDeleted
         self.createdAt = createdAt
         self.updatedAt = updatedAt
     }
@@ -232,10 +257,35 @@ struct BackupProblem: Codable {
             isActive: self.isActive,
             dateSet: self.dateSet,
             notes: self.notes,
+            isDeleted: self.isDeleted ?? false,
             createdAt: self.createdAt,
             updatedAt: self.updatedAt
         )
     }
+
+    static func createTombstone(id: String, gymId: String = UUID().uuidString, deletedAt: Date) -> BackupProblem {
+        let formatter = ISO8601DateFormatter()
+        formatter.formatOptions = [.withInternetDateTime, .withFractionalSeconds]
+        let dateString = formatter.string(from: deletedAt)
+
+        return BackupProblem(
+            id: id,
+            gymId: gymId,
+            name: "DELETED",
+            description: nil,
+            climbType: ClimbType.allCases.first!,
+            difficulty: DifficultyGrade(system: DifficultySystem.allCases.first!, grade: "0"),
+            tags: [],
+            location: nil,
+            imagePaths: nil,
+            isActive: false,
+            dateSet: nil,
+            notes: nil,
+            isDeleted: true,
+            createdAt: dateString,
+            updatedAt: dateString
+        )
+    }
 }
 
 // Platform-neutral climb session representation for backup/restore
@@ -248,6 +298,7 @@ struct BackupClimbSession: Codable {
     let duration: Int64?  // Duration in seconds
     let status: SessionStatus
     let notes: String?
+    let isDeleted: Bool?
     let createdAt: String
     let updatedAt: String
 
@@ -256,6 +307,7 @@ struct BackupClimbSession: Codable {
         self.gymId = session.gymId.uuidString
         self.status = session.status
         self.notes = session.notes
+        self.isDeleted = false // Default to false until model is updated
 
         let formatter = ISO8601DateFormatter()
         formatter.formatOptions = [.withInternetDateTime, .withFractionalSeconds]
@@ -276,6 +328,7 @@ struct BackupClimbSession: Codable {
         duration: Int64?,
         status: SessionStatus,
         notes: String?,
+        isDeleted: Bool = false,
         createdAt: String,
         updatedAt: String
     ) {
@@ -287,6 +340,7 @@ struct BackupClimbSession: Codable {
         self.duration = duration
         self.status = status
         self.notes = notes
+        self.isDeleted = isDeleted
         self.createdAt = createdAt
         self.updatedAt = updatedAt
     }
@@ -321,6 +375,26 @@ struct BackupClimbSession: Codable {
             updatedAt: updatedDate
         )
     }
+
+    static func createTombstone(id: String, gymId: String = UUID().uuidString, deletedAt: Date) -> BackupClimbSession {
+        let formatter = ISO8601DateFormatter()
+        formatter.formatOptions = [.withInternetDateTime, .withFractionalSeconds]
+        let dateString = formatter.string(from: deletedAt)
+
+        return BackupClimbSession(
+            id: id,
+            gymId: gymId,
+            date: dateString,
+            startTime: nil,
+            endTime: nil,
+            duration: nil,
+            status: .finished,
+            notes: nil,
+            isDeleted: true,
+            createdAt: dateString,
+            updatedAt: dateString
+        )
+    }
 }
 
 // Platform-neutral attempt representation for backup/restore
@@ -334,6 +408,7 @@ struct BackupAttempt: Codable {
     let duration: Int64?  // Duration in seconds
     let restTime: Int64?  // Rest time in seconds
     let timestamp: String
+    let isDeleted: Bool?
     let createdAt: String
     let updatedAt: String?
 
@@ -346,6 +421,7 @@ struct BackupAttempt: Codable {
         self.notes = attempt.notes
         self.duration = attempt.duration.map { Int64($0) }
         self.restTime = attempt.restTime.map { Int64($0) }
+        self.isDeleted = false // Default to false until model is updated
 
         let formatter = ISO8601DateFormatter()
         formatter.formatOptions = [.withInternetDateTime, .withFractionalSeconds]
@@ -364,6 +440,7 @@ struct BackupAttempt: Codable {
         duration: Int64?,
         restTime: Int64?,
         timestamp: String,
+        isDeleted: Bool = false,
         createdAt: String,
         updatedAt: String?
     ) {
@@ -376,6 +453,7 @@ struct BackupAttempt: Codable {
         self.duration = duration
         self.restTime = restTime
         self.timestamp = timestamp
+        self.isDeleted = isDeleted
         self.createdAt = createdAt
         self.updatedAt = updatedAt
     }
@@ -412,6 +490,27 @@ struct BackupAttempt: Codable {
             updatedAt: updatedDate
         )
     }
+
+    static func createTombstone(id: String, sessionId: String = UUID().uuidString, problemId: String = UUID().uuidString, deletedAt: Date) -> BackupAttempt {
+        let formatter = ISO8601DateFormatter()
+        formatter.formatOptions = [.withInternetDateTime, .withFractionalSeconds]
+        let dateString = formatter.string(from: deletedAt)
+
+        return BackupAttempt(
+            id: id,
+            sessionId: sessionId,
+            problemId: problemId,
+            result: AttemptResult.allCases.first!,
+            highestHold: nil,
+            notes: nil,
+            duration: nil,
+            restTime: nil,
+            timestamp: dateString,
+            isDeleted: true,
+            createdAt: dateString,
+            updatedAt: dateString
+        )
+    }
 }
 
 // MARK: - Backup Format Errors