Let routines rename exercises and repeat them for interval segments

An exercise's name is now a per-routine display name: a new optional
libraryName on ExerciseDocument (snapshotted onto WorkoutLogDocument at
plan time) keeps the link to the bundled library exercise, and every
figure/info/cue lookup resolves libraryName ?? name. Deliberately not
schema-bumped — an older app dropping the key only strands the
figure link, same rationale as activityType. Cache schema bumped to 9
for the new columns.

The picker no longer filters out exercises already in the routine
(an "×N" badge marks them instead), exercise rows gain a leading
Duplicate swipe that clones an entry in place, and the edit sheet gets
a Name field with the library exercise shown read-only above it.

Claude-Session: https://claude.ai/code/session_01H8VxUX4ckjU3vRF5M4L5FV

Shared/Model/Entities.swift

@@ -80,11 +80,15 @@ final class Exercise {
     // `Workout` stores `hrZoneSeconds` as a plain `[Double]?`. `nil` → not a
     // machine exercise; empty → a machine exercise with nothing recorded yet.
     var machineSettings: [MachineSetting]?
+    // The library exercise `name` was customized from; nil → `name` IS the
+    // library name. Mirrors `ExerciseDocument.libraryName`.
+    var libraryName: String?
 
     var routine: Routine?
 
     init(id: String, name: String, order: Int, sets: Int, reps: Int, weight: Double,
-         loadType: Int, durationTotalSeconds: Int, machineSettings: [MachineSetting]? = nil) {
+         loadType: Int, durationTotalSeconds: Int, machineSettings: [MachineSetting]? = nil,
+         libraryName: String? = nil) {
         self.id = id
         self.name = name
         self.order = order
@@ -94,6 +98,7 @@ final class Exercise {
         self.loadType = loadType
         self.durationTotalSeconds = durationTotalSeconds
         self.machineSettings = machineSettings
+        self.libraryName = libraryName
     }
 
     var loadTypeEnum: LoadType {
@@ -101,6 +106,9 @@ final class Exercise {
         set { loadType = newValue.rawValue }
     }
 
+    /// The name to resolve figure/info/cues against — see `ExerciseDocument.libraryExerciseName`.
+    var libraryExerciseName: String { libraryName ?? name }
+
     /// One-line plan summary for list rows — duration exercises show their hold time
     /// ("3 × 45 sec"), unloaded ones drop the weight ("3 × 12 reps"), weighted ones
     /// keep the full "3 × 10 × 40 lb".
@@ -270,6 +278,9 @@ final class WorkoutLog {
     // Mirrors the document's per-log `updatedAt` (named to dodge a future
     // SwiftData column collision). Reserved for H1's per-log merge; unused.
     var logUpdatedAt: Date?
+    // Plan-time snapshot of the exercise's `libraryName`. Mirrors
+    // `WorkoutLogDocument.libraryName`.
+    var libraryName: String?
 
     var workout: Workout?
 
@@ -278,7 +289,8 @@ final class WorkoutLog {
          statusRaw: String, notes: String?, date: Date,
          machineSettings: [MachineSetting]? = nil,
          startedAt: Date? = nil, completedAt: Date? = nil,
-         setEntries: [SetEntry]? = nil, logUpdatedAt: Date? = nil) {
+         setEntries: [SetEntry]? = nil, logUpdatedAt: Date? = nil,
+         libraryName: String? = nil) {
         self.id = id
         self.exerciseName = exerciseName
         self.order = order
@@ -296,6 +308,7 @@ final class WorkoutLog {
         self.completedAt = completedAt
         self.setEntries = setEntries
         self.logUpdatedAt = logUpdatedAt
+        self.libraryName = libraryName
     }
 
     var status: WorkoutStatus {
@@ -308,6 +321,9 @@ final class WorkoutLog {
         set { loadType = newValue.rawValue }
     }
 
+    /// The name to resolve figure/info/cues against — see `ExerciseDocument.libraryExerciseName`.
+    var libraryExerciseName: String { libraryName ?? exerciseName }
+
     var durationMinutes: Int {
         get { durationTotalSeconds / 60 }
         set { durationTotalSeconds = newValue * 60 + durationSeconds }