wallpaper: engine page commits like the others, Start changes at once

The page was the only settings page without the header's buttons, and
it switched the engine from a checkbox beside the interval. Both looked
like the engine had been started when it had not:

- The minutes field saved on editingFinished, which needs Enter or a
  focus change. Clicking the checkbox takes neither, so a typed 1 was
  left at 30 and the first change was half an hour away.
- Even at the right interval, the first change waited one full
  interval, so starting the engine did nothing visible.

The interval and the two sources are now a draft in WallEngine, updated
on every keystroke, and the header carries the state ("running, next
change at hh:mm", "stopped", "unsaved changes") with Reset, Stop and
Start, which reads Apply while running. Start commits the draft, sets
the homes and changes the wallpapers straight away; Apply commits and
restarts the timer. Hearts stay undrafted, written as clicked.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

1 files changed, 15 insertions, 13 deletions

diff --git a/desktop/modules/appearance/WallEngineTab.qml b/desktop/modules/appearance/WallEngineTab.qml
index caa01f4..3f72d83 100644
--- a/desktop/modules/appearance/WallEngineTab.qml
+++ b/desktop/modules/appearance/WallEngineTab.qml
@@ -22,20 +22,21 @@ Item {
 
         Row {
             spacing: 8
-            Toggle {
+            Text {
                 anchors.verticalCenter: parent.verticalCenter
-                checked: WallEngine.on
-                label: "Change the wallpapers every"
-                onToggled: WallEngine.setOn(checked)
+                text: "Change the wallpapers every"
+                color: Theme.subtext
+                font { family: Theme.fontFamily; pixelSize: Theme.fontSize - 4 }
             }
             Field {
                 anchors.verticalCenter: parent.verticalCenter
                 width: 50
-                value: String(WallEngine.cfg.minutes)
-                onEdited: {
-                    WallEngine.setMinutes(Number(value));
-                    value = String(WallEngine.cfg.minutes);
-                }
+                value: String(WallEngine.draftMinutes)
+                // On every keystroke, not on edited: that waits for Enter
+                // or a focus change, and clicking Start takes neither, so a
+                // typed interval was silently left at the old one.
+                onValueChanged: WallEngine.setDraftMinutes(Number(value))
+                onEdited: value = String(WallEngine.draftMinutes)
             }
             Text {
                 anchors.verticalCenter: parent.verticalCenter
@@ -54,7 +55,7 @@ Item {
             width: col.width
             wrapMode: Text.Wrap
             text: "Timer changes recolour the desktop and leave GRUB, the homepage and the login screen alone. "
-                + "Switching off puts back each screen's home wallpaper, the one last applied by hand, with a full run."
+                + "Stop puts back each screen's home wallpaper, the one last applied by hand, with a full run."
             color: Theme.overlay
             font { family: Theme.fontFamily; pixelSize: Theme.fontSize - 4 }
         }
@@ -67,7 +68,8 @@ Item {
                 required property var modelData
                 readonly property var paths: WallEngine.list(modelData.which)
                 readonly property string home: modelData.which === "V" ? WallEngine.cfg.homeV : WallEngine.cfg.homeH
-                readonly property string folder: WallEngine.folder(modelData.which)
+                // The draft's source: what Start or Apply will use.
+                readonly property string folder: WallEngine.draftFolder(modelData.which)
                 readonly property var group: Wallpapers.groups.find(g => g.key === folder) ?? null
                 width: col.width
                 spacing: 8
@@ -90,7 +92,7 @@ Item {
                     Tab {
                         text: "Hearted"
                         selected: screen.folder === ""
-                        onClicked: WallEngine.setFolder(screen.modelData.which, "")
+                        onClicked: WallEngine.setDraftFolder(screen.modelData.which, "")
                     }
                     Repeater {
                         model: Wallpapers.groups
@@ -98,7 +100,7 @@ Item {
                             required property var modelData
                             text: modelData.name
                             selected: screen.folder === modelData.key
-                            onClicked: WallEngine.setFolder(screen.modelData.which, modelData.key)
+                            onClicked: WallEngine.setDraftFolder(screen.modelData.which, modelData.key)
                         }
                     }
                 }