Fix 28 issues from deep audit and UI audit + redesign changes

Deep audit (issues 2-14):
- Add missing WCSession handlers for applicationContext and userInfo
- Fix BoundedFIFOQueue race condition with serial dispatch queue
- Fix timer race condition with main thread guarantee
- Fix watch pause state divergence — phone is now source of truth
- Fix wrong notification posted on logout (createdNewWorkout → userLoggedOut)
- Fix POST status check to accept any 2xx (was exact match)
- Fix @StateObject → @ObservedObject for injected viewModel
- Add pull-to-refresh to CompletedWorkoutsView
- Fix typos: RefreshUserInfoFetcable, defualtPackageModle
- Replace string concatenation with interpolation
- Replace 6 @StateObject with @ObservedObject for BridgeModule.shared
- Replace 7 hardcoded AVPlayer URLs with BaseURLs.currentBaseURL

UI audit (issues 1-15):
- Fix GeometryReader eating VStack space — replaced with .overlay
- Fix refreshable continuation resuming before fetch completes
- Remove duplicate @State workouts — derive from DataStore
- Decouple leaf views from BridgeModule (pass discrete values)
- Convert selectedIds from Array to Set for O(1) lookups
- Extract .sorted() from var body into computed properties
- Move search filter out of ForEach render loop
- Replace import SwiftUI with import Combine in non-UI classes
- Mark all @State properties private
- Extract L/R exercise auto-add logic to WorkoutViewModel
- Use enumerated() instead of .indices in ForEach
- Make AddSupersetView frame flexible instead of fixed 300pt
- Hoist Set construction out of per-exercise filter loop
- Move ViewModel network fetch from init to load()

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

SharedCore/Package.swift

@@ -1,10 +1,10 @@
-// swift-tools-version: 5.9
+// swift-tools-version: 6.2
 import PackageDescription
 
 let package = Package(
     name: "SharedCore",
     platforms: [
-        .iOS(.v16),
+        .iOS(.v26),
         .watchOS(.v9),
         .tvOS(.v16),
         .macOS(.v13)
@@ -31,5 +31,6 @@ let package = Package(
             name: "SharedCoreTVOSTests",
             dependencies: ["SharedCore"]
         )
-    ]
+    ],
+    swiftLanguageModes: [.v5]
 )

SharedCore/Sources/SharedCore/AppNotifications.swift

@@ -2,5 +2,6 @@ import Foundation
 
 public enum AppNotifications {
     public static let createdNewWorkout = Notification.Name("CreatedNewWorkout")
+    public static let userLoggedOut = Notification.Name("UserLoggedOut")
 }