Add CoreData-based workout tracking app with iOS and watchOS targets

- Migrate from SwiftData to CoreData with CloudKit sync
- Add core models: Split, Exercise, Workout, WorkoutLog
- Implement tab-based UI: Workout Logs, Splits, Settings
- Add SF Symbols picker for split icons
- Add exercise picker filtered by split with exclusion of added exercises
- Integrate IndieAbout for settings/about section
- Add Yams for YAML exercise definition parsing
- Include starter exercise libraries (bodyweight, Planet Fitness)
- Add Date extensions for formatting (formattedTime, isSameDay)
- Format workout date ranges to show time-only for same-day end dates
- Add build number update script
- Add app icons

Workouts/Models/Workout.swift

@@ -0,0 +1,83 @@
+import Foundation
+import CoreData
+
+@objc(Workout)
+public class Workout: NSManagedObject, Identifiable {
+    @NSManaged public var start: Date
+    @NSManaged public var end: Date?
+
+    @NSManaged public var split: Split?
+    @NSManaged public var logs: NSSet?
+
+    public var id: NSManagedObjectID { objectID }
+
+    var status: WorkoutStatus {
+        get {
+            willAccessValue(forKey: "status")
+            let raw = primitiveValue(forKey: "status") as? String ?? "notStarted"
+            didAccessValue(forKey: "status")
+            return WorkoutStatus(rawValue: raw) ?? .notStarted
+        }
+        set {
+            willChangeValue(forKey: "status")
+            setPrimitiveValue(newValue.rawValue, forKey: "status")
+            didChangeValue(forKey: "status")
+        }
+    }
+
+    var label: String {
+        if status == .completed, let endDate = end {
+            if start.isSameDay(as: endDate) {
+                return "\(start.formattedDate())—\(endDate.formattedTime())"
+            } else {
+                return "\(start.formattedDate())—\(endDate.formattedDate())"
+            }
+        } else {
+            return start.formattedDate()
+        }
+    }
+
+    var statusName: String {
+        return status.displayName
+    }
+}
+
+// MARK: - Convenience Accessors
+
+extension Workout {
+    var logsArray: [WorkoutLog] {
+        let set = logs as? Set<WorkoutLog> ?? []
+        return set.sorted { $0.order < $1.order }
+    }
+
+    func addToLogs(_ log: WorkoutLog) {
+        let items = mutableSetValue(forKey: "logs")
+        items.add(log)
+    }
+
+    func removeFromLogs(_ log: WorkoutLog) {
+        let items = mutableSetValue(forKey: "logs")
+        items.remove(log)
+    }
+}
+
+// MARK: - Fetch Request
+
+extension Workout {
+    @nonobjc public class func fetchRequest() -> NSFetchRequest<Workout> {
+        return NSFetchRequest<Workout>(entityName: "Workout")
+    }
+
+    static func recentFetchRequest() -> NSFetchRequest<Workout> {
+        let request = fetchRequest()
+        request.sortDescriptors = [NSSortDescriptor(keyPath: \Workout.start, ascending: false)]
+        return request
+    }
+
+    static func fetchRequest(for split: Split) -> NSFetchRequest<Workout> {
+        let request = fetchRequest()
+        request.predicate = NSPredicate(format: "split == %@", split)
+        request.sortDescriptors = [NSSortDescriptor(keyPath: \Workout.start, ascending: false)]
+        return request
+    }
+}