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/Mappers.swift

@@ -38,7 +38,8 @@ extension WorkoutLogDocument {
                   durationSeconds: log.durationTotalSeconds, currentStateIndex: log.currentStateIndex,
                   status: log.statusRaw, notes: log.notes, date: log.date,
                   machineSettings: log.machineSettings,
-                  startedAt: log.startedAt, completedAt: log.completedAt)
+                  startedAt: log.startedAt, completedAt: log.completedAt,
+                  setEntries: log.setEntries, updatedAt: log.logUpdatedAt)
     }
 }
 
@@ -167,7 +168,8 @@ enum CacheMapper {
                    weight: d.weight, loadType: d.loadType, durationTotalSeconds: d.durationSeconds,
                    currentStateIndex: d.currentStateIndex, statusRaw: d.status,
                    notes: d.notes, date: d.date, machineSettings: d.machineSettings,
-                   startedAt: d.startedAt, completedAt: d.completedAt)
+                   startedAt: d.startedAt, completedAt: d.completedAt,
+                   setEntries: d.setEntries, logUpdatedAt: d.updatedAt)
     }
 
     private static func apply(_ d: WorkoutLogDocument, to l: WorkoutLog) {
@@ -185,5 +187,7 @@ enum CacheMapper {
         l.machineSettings = d.machineSettings
         l.startedAt = d.startedAt
         l.completedAt = d.completedAt
+        l.setEntries = d.setEntries
+        l.logUpdatedAt = d.updatedAt
     }
 }