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

Workouts/Views/WorkoutLogs/ExerciseView.swift

@@ -119,7 +119,7 @@ struct ExerciseView: View {
             // any exercise the authored library identifies as machine-based, so the
             // section is discoverable before settings are first recorded.
             if log.machineSettings != nil
-                || ExerciseInfoLibrary.info(for: log.exerciseName)?.isMachineBased == true {
+                || ExerciseInfoLibrary.info(for: log.libraryExerciseName)?.isMachineBased == true {
                 let settings = log.machineSettings ?? []
                 Section {
                     if settings.isEmpty {