Restructure into a three-tab app with Progress, goals, and Meditation

The UX redesign's first landing (spec in UX-REDESIGN.md): ContentView
becomes a Today / Progress / Settings TabView, "Routine" replaces
"Split" in every user-facing string and view name (code-level types
keep their names), and workout starting moves to shared
WorkoutStarter / StartedWorkoutNavigator plumbing.

- New Progress tab: weekly goal streaks, workout trends, per-exercise
  weight progression, achievements, and the full history list
  (WorkoutLogsView -> WorkoutHistoryView).
- Goals: stable categories workouts roll up to, managed from Settings.
- New Meditation exercise + starter routine; timed sits record to
  Apple Health as Mind & Body sessions.

Claude-Session: https://claude.ai/code/session_012qw2itfzKyEJ1HpsFt8Ex4

Shared/Model/Entities.swift

@@ -11,10 +11,10 @@ import SwiftData
 // SwiftData PersistentIdentifier). Computed helpers preserve the API the views
 // used against the old Core Data classes.
 
-// MARK: - Split
+// MARK: - Routine
 
 @Model
-final class Split {
+final class Routine {
     @Attribute(.unique) var id: String = ULID.make()
     var name: String = ""
     var color: String = "indigo"
@@ -27,7 +27,7 @@ final class Split {
     var restSeconds: Int?
     var autoAdvance: Bool?
 
-    @Relationship(deleteRule: .cascade, inverse: \Exercise.split)
+    @Relationship(deleteRule: .cascade, inverse: \Exercise.routine)
     var exercises: [Exercise] = []
 
     init(id: String, name: String, color: String, systemImage: String, order: Int,
@@ -42,7 +42,7 @@ final class Split {
         self.jsonRelativePath = jsonRelativePath
     }
 
-    static let unnamed = "Unnamed Split"
+    static let unnamed = "Unnamed Routine"
 
     var exercisesArray: [Exercise] { exercises.sorted { $0.order < $1.order } }
 
@@ -70,7 +70,7 @@ final class Exercise {
     // machine exercise; empty → a machine exercise with nothing recorded yet.
     var machineSettings: [MachineSetting]?
 
-    var split: Split?
+    var routine: Routine?
 
     init(id: String, name: String, order: Int, sets: Int, reps: Int, weight: Double,
          loadType: Int, durationTotalSeconds: Int, machineSettings: [MachineSetting]? = nil) {
@@ -124,8 +124,8 @@ final class Exercise {
 @Model
 final class Workout {
     @Attribute(.unique) var id: String = ULID.make()
-    var splitID: String?
-    var splitName: String?
+    var routineID: String?
+    var routineName: String?
     var start: Date = Date()
     var end: Date?
     var statusRaw: String = WorkoutStatus.notStarted.rawValue
@@ -156,11 +156,11 @@ final class Workout {
     @Relationship(deleteRule: .cascade, inverse: \WorkoutLog.workout)
     var logs: [WorkoutLog] = []
 
-    init(id: String, splitID: String?, splitName: String?, start: Date, end: Date?,
+    init(id: String, routineID: String?, routineName: String?, start: Date, end: Date?,
          statusRaw: String, createdAt: Date, updatedAt: Date, jsonRelativePath: String) {
         self.id = id
-        self.splitID = splitID
-        self.splitName = splitName
+        self.routineID = routineID
+        self.routineName = routineName
         self.start = start
         self.end = end
         self.statusRaw = statusRaw
@@ -174,6 +174,14 @@ final class Workout {
         set { statusRaw = newValue.rawValue }
     }
 
+    /// True while this workout is an untouched draft: created by a start tap, but no
+    /// exercise has ever left `.notStarted`. Peeking into a routine must leave no
+    /// trace, so the start paths discard a pristine draft when the user backs out of
+    /// it instead of persisting a phantom "in progress" workout.
+    var isPristineDraft: Bool {
+        status == .notStarted && logs.allSatisfy { $0.status == .notStarted }
+    }
+
     var statusName: String { status.displayName }
 
     var logsArray: [WorkoutLog] { logs.sorted { $0.order < $1.order } }
@@ -298,3 +306,54 @@ final class WorkoutLog {
         set { durationTotalSeconds = durationMinutes * 60 + newValue }
     }
 }
+
+// MARK: - Schedule
+
+@Model
+final class Schedule {
+    @Attribute(.unique) var id: String = ULID.make()
+    var routineID: String = ""
+    var routineName: String = ""
+    var goalRaw: String?
+    var recurrenceRaw: String = ScheduleRecurrence.daily.rawValue
+    var weekdays: [Int]?
+    var timesPerWeek: Int?
+    var date: Date?
+    var order: Int = 0
+    var createdAt: Date = Date()
+    var updatedAt: Date = Date()
+    var jsonRelativePath: String = ""
+
+    init(id: String, routineID: String, routineName: String, goalRaw: String?,
+         recurrenceRaw: String, weekdays: [Int]?, timesPerWeek: Int?, date: Date? = nil,
+         order: Int, createdAt: Date, updatedAt: Date, jsonRelativePath: String) {
+        self.id = id
+        self.routineID = routineID
+        self.routineName = routineName
+        self.goalRaw = goalRaw
+        self.recurrenceRaw = recurrenceRaw
+        self.weekdays = weekdays
+        self.timesPerWeek = timesPerWeek
+        self.date = date
+        self.order = order
+        self.createdAt = createdAt
+        self.updatedAt = updatedAt
+        self.jsonRelativePath = jsonRelativePath
+    }
+
+    var goalKind: GoalKind? {
+        get { goalRaw.flatMap(GoalKind.init(rawValue:)) }
+        set { goalRaw = newValue?.rawValue }
+    }
+
+    var recurrenceEnum: ScheduleRecurrence {
+        get { ScheduleRecurrence(rawValue: recurrenceRaw) ?? .daily }
+        set { recurrenceRaw = newValue.rawValue }
+    }
+
+    /// Human-readable recurrence line — shares its formatting with `ScheduleDocument`
+    /// via `ScheduleRecurrence.summary(weekdays:timesPerWeek:date:)`.
+    var recurrenceSummary: String {
+        recurrenceEnum.summary(weekdays: weekdays, timesPerWeek: timesPerWeek, date: date)
+    }
+}