Add machine comfort settings and tighten the document schemas

Machine-based exercises now carry ordered name/value comfort settings
(seat height, back-rest position, ...) on both ExerciseDocument and, as a
plan-time snapshot, WorkoutLogDocument — the optional array doubles as the
machine flag. Editable from the exercise editor's new Machine section and
from the workout row's settings sheet, whose mid-workout edits write back
to the originating split (workout saved first, so seed clone-on-edit
repointing can't clobber the log edit).

Schema tightening rides the same rev: splits bump to v2 (weight-reminder
fields and the unused exercise category removed), workouts to v3 (the
derived `completed` flag removed; status is the single source). Starter
seeds regenerated at v2 with unchanged ULIDs; SwiftData cache schema
bumped to rebuild. SCHEMA.md documents the shapes.

Claude-Session: https://claude.ai/code/session_01LEoff8bXGBS83tK1c55Mf7

Workouts/Views/Common/CheckboxListItem.swift

@@ -1,52 +0,0 @@
-//
-// CheckboxListItem.swift
-// Workouts
-//
-// Created by rzen on 7/13/25 at 10:42 AM.
-//
-// Copyright 2025 Rouslan Zenetl. All Rights Reserved.
-//
-
-import SwiftUI
-
-struct CheckboxListItem: View {
-    var status: CheckboxStatus
-    var title: String
-    var subtitle: String?
-    var count: Int?
-    var onCheckboxTap: (() -> Void)? = nil
-
-    var body: some View {
-        HStack(alignment: .top) {
-            Button {
-                onCheckboxTap?()
-            } label: {
-                Image(systemName: status.systemName)
-                    .resizable()
-                    .scaledToFit()
-                    .frame(width: 30, height: 30)
-                    .foregroundStyle(status.color)
-            }
-            .buttonStyle(.plain)
-            VStack(alignment: .leading) {
-                Text("\(title)")
-                    .font(.headline)
-                    .foregroundColor(.primary)
-                HStack(alignment: .bottom) {
-                    if let subtitle = subtitle {
-                        Text("\(subtitle)")
-                            .font(.footnote)
-                            .foregroundColor(.secondary)
-                    }
-                }
-            }
-            Spacer()
-            if let count = count {
-                Text("\(count)")
-                    .font(.caption)
-                    .foregroundColor(.gray)
-            }
-        }
-        .frame(maxWidth: .infinity, alignment: .leading)
-    }
-}

Workouts/Views/Common/CheckboxStatus.swift

@@ -19,8 +19,8 @@ enum CheckboxStatus {
         switch self {
         case .checked: .accentColor
         case .unchecked: .gray
-        case .intermediate: .gray
-        case .cancelled: .red
+        case .intermediate: .accentColor
+        case .cancelled: .gray
         }
     }
 
@@ -29,7 +29,7 @@ enum CheckboxStatus {
         case .checked: "checkmark.circle.fill"
         case .unchecked: "circle"
         case .intermediate: "ellipsis.circle"
-        case .cancelled: "xmark.circle"
+        case .cancelled: "wrongwaysign"
         }
     }
 }

Workouts/Views/Common/MachineSettingsEditor.swift

@@ -0,0 +1,70 @@
+//
+// MachineSettingsEditor.swift
+// Workouts
+//
+// Copyright 2025 Rouslan Zenetl. All Rights Reserved.
+//
+
+import SwiftUI
+
+/// Reusable editor for an ordered list of machine comfort settings (seat height,
+/// back-rest incline, pin position…). Drop it into a `Form`/`List` `Section`: it
+/// renders one `name`/`value` row per setting with swipe-to-delete and
+/// drag-to-reorder, plus an "Add Setting" row. Shared by the exercise add/edit
+/// screen (Surface 1) and the in-workout settings sheet (Surface 2).
+///
+/// `MachineSetting` is a plain Codable wire type with no identity, so the editor
+/// keeps a per-row `UUID` internally (stable across edits/reorders, unlike an
+/// index) and mirrors changes back into the `settings` binding. The editor is the
+/// sole mutator of `settings` while it's on screen, so a one-way seed at init is
+/// enough — there's no external write to reconcile.
+struct MachineSettingsEditor: View {
+    @Binding var settings: [MachineSetting]
+    @State private var rows: [Row]
+
+    init(settings: Binding<[MachineSetting]>) {
+        _settings = settings
+        _rows = State(initialValue: settings.wrappedValue.map(Row.init))
+    }
+
+    var body: some View {
+        ForEach($rows) { $row in
+            HStack {
+                TextField("Setting", text: $row.name)
+                    .textInputAutocapitalization(.words)
+                TextField("Value", text: $row.value)
+                    .multilineTextAlignment(.trailing)
+                    .foregroundStyle(.secondary)
+                    .frame(maxWidth: 120)
+            }
+        }
+        .onDelete { rows.remove(atOffsets: $0) }
+        .onMove { rows.move(fromOffsets: $0, toOffset: $1) }
+
+        Button {
+            withAnimation { rows.append(Row(MachineSetting(name: "", value: ""))) }
+        } label: {
+            Label("Add Setting", systemImage: "plus.circle.fill")
+        }
+        // Mirror the identified rows back into the plain wire-type binding on every
+        // edit/add/delete/reorder.
+        .onChange(of: rows) { _, newRows in
+            settings = newRows.map(\.setting)
+        }
+    }
+
+    /// Session-only identified wrapper so `ForEach` and reordering have a stable
+    /// identity that survives text edits.
+    fileprivate struct Row: Identifiable, Equatable {
+        let id = UUID()
+        var name: String
+        var value: String
+
+        init(_ setting: MachineSetting) {
+            name = setting.name
+            value = setting.value
+        }
+
+        var setting: MachineSetting { MachineSetting(name: name, value: value) }
+    }
+}