Refactor UI: move Splits to Settings, redesign ExerciseView

Schema & Models:
- Add notes, loadType, duration fields to WorkoutLog
- Align Watch schema with iOS (use duration Date instead of separate mins/secs)
- Add duration helper properties to Exercise and WorkoutLog

UI Changes:
- Remove Splits and Settings tabs, single Workout Logs view
- Add gear button in nav bar to access Settings as sheet
- Move Splits section into Settings view with inline list
- Redesign ExerciseView with read-only Plan/Notes tiles and Edit buttons
- Add PlanEditView and NotesEditView with Cancel/Save buttons
- Auto-dismiss ExerciseView when completing last set
- Navigate to ExerciseView when adding new exercise

Data Flow:
- Plan edits sync to both WorkoutLog and corresponding Exercise
- Changes propagate up navigation chain via CoreData

Workouts/Views/WorkoutLogs/WorkoutLogsView.swift

@@ -20,6 +20,7 @@ struct WorkoutLogsView: View {
     private var workouts: FetchedResults<Workout>
 
     @State private var showingSplitPicker = false
+    @State private var showingSettings = false
     @State private var itemToDelete: Workout? = nil
 
     var body: some View {
@@ -55,12 +56,22 @@ struct WorkoutLogsView: View {
             }
             .navigationTitle("Workout Logs")
             .toolbar {
+                ToolbarItem(placement: .navigationBarLeading) {
+                    Button {
+                        showingSettings = true
+                    } label: {
+                        Image(systemName: "gearshape.2")
+                    }
+                }
                 ToolbarItem(placement: .navigationBarTrailing) {
                     Button("Start New") {
                         showingSplitPicker.toggle()
                     }
                 }
             }
+            .sheet(isPresented: $showingSettings) {
+                SettingsView()
+            }
             .sheet(isPresented: $showingSplitPicker) {
                 SplitPickerSheet()
             }