Record per-set actuals and drive the chart and volume from them

Every completed set now writes a SetEntry (reps/weight or seconds),
pre-filled from the plan by transition(to:) so the list checkbox, both
run flows, and One More all capture for free; reset clears, skip keeps
partials. The rest and finish pages show the just-done set as a pill
that opens a stepper sheet for correcting reps and weight (2.5 lb /
1.25 kg steps). The Weight Progression chart plots the top-set actual
weight and workout volume sums recorded sets, both falling back to the
plan for legacy logs via effectiveSetEntries.

Storage side of UX #3 rides along: plan weights are Double now.
Schema bumps: SplitDocument 2→3, WorkoutDocument 3→4 (a fractional
weight fails an older Int decode, and a rewrite would strip the
irreplaceable actuals), SwiftData cache 4→5. A per-log updatedAt is
reserved for the future cross-device log merge.

Claude-Session: https://claude.ai/code/session_01HJDQQDA9QdP8zByg43H5v3

Shared/Model/Entities.swift

@@ -59,7 +59,7 @@ final class Exercise {
     var order: Int = 0
     var sets: Int = 0
     var reps: Int = 0
-    var weight: Int = 0
+    var weight: Double = 0
     var loadType: Int = LoadType.weight.rawValue
     var durationTotalSeconds: Int = 0
     // Machine comfort settings — stored directly as an optional Codable array
@@ -70,7 +70,7 @@ final class Exercise {
 
     var split: Split?
 
-    init(id: String, name: String, order: Int, sets: Int, reps: Int, weight: Int,
+    init(id: String, name: String, order: Int, sets: Int, reps: Int, weight: Double,
          loadType: Int, durationTotalSeconds: Int, machineSettings: [MachineSetting]? = nil) {
         self.id = id
         self.name = name
@@ -223,7 +223,7 @@ final class WorkoutLog {
     var order: Int = 0
     var sets: Int = 0
     var reps: Int = 0
-    var weight: Int = 0
+    var weight: Double = 0
     var loadType: Int = LoadType.weight.rawValue
     var durationTotalSeconds: Int = 0
     var currentStateIndex: Int = 0
@@ -235,14 +235,21 @@ final class WorkoutLog {
     var machineSettings: [MachineSetting]?
     var startedAt: Date?
     var completedAt: Date?
+    // Per-set actuals — stored directly as an optional Codable array, same
+    // pattern as `machineSettings`. `nil` → legacy file / nothing recorded.
+    var setEntries: [SetEntry]?
+    // 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?
 
     var workout: Workout?
 
-    init(id: String, exerciseName: String, order: Int, sets: Int, reps: Int, weight: Int,
+    init(id: String, exerciseName: String, order: Int, sets: Int, reps: Int, weight: Double,
          loadType: Int, durationTotalSeconds: Int, currentStateIndex: Int,
          statusRaw: String, notes: String?, date: Date,
          machineSettings: [MachineSetting]? = nil,
-         startedAt: Date? = nil, completedAt: Date? = nil) {
+         startedAt: Date? = nil, completedAt: Date? = nil,
+         setEntries: [SetEntry]? = nil, logUpdatedAt: Date? = nil) {
         self.id = id
         self.exerciseName = exerciseName
         self.order = order
@@ -258,6 +265,8 @@ final class WorkoutLog {
         self.machineSettings = machineSettings
         self.startedAt = startedAt
         self.completedAt = completedAt
+        self.setEntries = setEntries
+        self.logUpdatedAt = logUpdatedAt
     }
 
     var status: WorkoutStatus {