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

WorkoutsTests/WorkoutDocumentMapperTests.swift

@@ -34,13 +34,16 @@ struct WorkoutDocumentMapperTests {
 
     private func log(
         id: String, name: String, order: Int, status: WorkoutStatus,
-        machineSettings: [MachineSetting]? = nil, startedAt: Date? = nil, completedAt: Date? = nil
+        weight: Double = 135, machineSettings: [MachineSetting]? = nil,
+        startedAt: Date? = nil, completedAt: Date? = nil,
+        setEntries: [SetEntry]? = nil, updatedAt: Date? = nil
     ) -> WorkoutLogDocument {
         WorkoutLogDocument(
-            id: id, exerciseName: name, order: order, sets: 4, reps: 10, weight: 135,
+            id: id, exerciseName: name, order: order, sets: 4, reps: 10, weight: weight,
             loadType: LoadType.weight.rawValue, durationSeconds: 0, currentStateIndex: 2,
             status: status.rawValue, notes: "note-\(name)", date: Self.logDate,
-            machineSettings: machineSettings, startedAt: startedAt, completedAt: completedAt
+            machineSettings: machineSettings, startedAt: startedAt, completedAt: completedAt,
+            setEntries: setEntries, updatedAt: updatedAt
         )
     }
 
@@ -64,11 +67,18 @@ struct WorkoutDocumentMapperTests {
             start: Self.start, end: Self.end, status: WorkoutStatus.completed.rawValue,
             createdAt: Self.created, updatedAt: Self.updated,
             logs: [
-                // order 0: not a machine exercise (nil), never started.
+                // order 0: not a machine exercise (nil), never started, no entries.
                 log(id: "LOG-A", name: "Bench Press", order: 0, status: .notStarted, machineSettings: nil),
-                // order 1: machine exercise, nothing recorded yet (empty ≠ nil), completed with timestamps.
-                log(id: "LOG-B", name: "Leg Press", order: 1, status: .completed, machineSettings: [],
-                    startedAt: Self.startedAt, completedAt: Self.completedAt),
+                // order 1: machine exercise, nothing recorded yet (empty ≠ nil), completed with
+                // timestamps, a fractional weight, recorded per-set actuals, and a per-log updatedAt.
+                log(id: "LOG-B", name: "Leg Press", order: 1, status: .completed,
+                    weight: 42.5, machineSettings: [],
+                    startedAt: Self.startedAt, completedAt: Self.completedAt,
+                    setEntries: [
+                        SetEntry(reps: 10, weight: 42.5, completedAt: Self.startedAt),
+                        SetEntry(reps: 8, weight: 45, completedAt: Self.completedAt),
+                    ],
+                    updatedAt: Self.updated),
                 // order 2: machine exercise with recorded settings, skipped.
                 log(id: "LOG-C", name: "Chest Press", order: 2, status: .skipped,
                     machineSettings: [MachineSetting(name: "Seat Height", value: "4"),
@@ -95,9 +105,17 @@ struct WorkoutDocumentMapperTests {
         #expect(rebuilt.status == WorkoutStatus.completed.rawValue)
         #expect(rebuilt.logs.count == 3)
         #expect(rebuilt.logs[0].machineSettings == nil)      // not a machine exercise
+        #expect(rebuilt.logs[0].setEntries == nil)           // nothing recorded stays nil
+        #expect(rebuilt.logs[0].updatedAt == nil)
         #expect(rebuilt.logs[1].machineSettings == [])       // machine, nothing recorded
         #expect(rebuilt.logs[1].startedAt == Self.startedAt)
         #expect(rebuilt.logs[1].completedAt == Self.completedAt)
+        #expect(rebuilt.logs[1].weight == 42.5)              // fractional weight survives
+        #expect(rebuilt.logs[1].setEntries == [
+            SetEntry(reps: 10, weight: 42.5, completedAt: Self.startedAt),
+            SetEntry(reps: 8, weight: 45, completedAt: Self.completedAt),
+        ])
+        #expect(rebuilt.logs[1].updatedAt == Self.updated)   // per-log merge stamp survives
         #expect(rebuilt.logs[2].machineSettings?.count == 2)
         #expect(rebuilt.metrics == fullMetrics())
         #expect(rebuilt.metrics?.hrZoneSeconds == [10, 20, 30, 40, 50])