The Background tab fills in — facets rendered to order, eight hues in a carousel

Claude-Session: https://claude.ai/code/session_01SR4XGjmBE16ZUYWpfFHXwY

Kanban/History/CardWindowUndo.swift

@@ -271,6 +271,8 @@ public final class CardWindowUndo {
             return .path(url.standardizedFileURL)
         }
 
-        private static let fieldOrder: [ExpectedField.Kind] = [.title, .order, .width, .background, .icon, .body]
+        private static let fieldOrder: [ExpectedField.Kind] = [
+            .title, .order, .width, .background, .backgroundImage, .icon, .body,
+        ]
     }
 }

Kanban/History/HistoryStaleness.swift

@@ -30,6 +30,15 @@ public enum ExpectedField: Sendable, Equatable {
     /// `background` — the styling gesture's colour dimension.
     case background(String?)
 
+    /// The `background` mapping's **`image` subkey** — the generated-background gesture's other half
+    /// (`BoardStore.applyGeneratedBackground`).
+    ///
+    /// Its own case rather than a second reading of `.background`, because they are two independent
+    /// values under one key: a board can have its colour changed from the wells while its image
+    /// stays, and the step that wrote the image must not stale because somebody picked a colour
+    /// afterwards. `nil` is the absent subkey, exactly as everywhere else here.
+    case backgroundImage(String?)
+
     /// `icon` — the styling gesture's symbol dimension.
     case icon(String?)
 
@@ -46,6 +55,7 @@ public enum ExpectedField: Sendable, Equatable {
         case .order: .order
         case .width: .width
         case .background: .background
+        case .backgroundImage: .backgroundImage
         case .icon: .icon
         case .body: .body
         }
@@ -58,6 +68,7 @@ public enum ExpectedField: Sendable, Equatable {
         case order
         case width
         case background
+        case backgroundImage
         case icon
         case body
     }
@@ -319,6 +330,7 @@ public enum HistoryStaleness {
         case let .order(expected): document.order.value == expected
         case let .width(expected): equal(document.width, expected)
         case let .background(expected): equal(document.background, expected)
+        case let .backgroundImage(expected): equal(document.backgroundImage, expected)
         case let .icon(expected): equal(document.icon, expected)
         case let .body(expected): document.body == expected
         }