fix(qt): elevated controls lift on hover instead of darkening

Buttons that rest on surfaceElevated used surfaceHover for their hover
fill: a 6% white wash meant for rows that rest transparent. Over an
elevated button it lands DARKER than the rest fill — on a modal's dark
ground the Cancel/Save/footer buttons went near-black under the pointer.

QbzTheme gains surfaceElevatedHover (a lift of surfaceElevated, derived
so every palette has it), its ambient half-alpha twin, and the
elevatedFill / elevatedHoverFill pair an ambient-aware control paints.
Every site with the old pairing (65 across modals, toolbars, selects,
circle actions, chips and cards) now hovers to the lift.

cc

crates/qbz-qt/qml/settings/DacWizardModal.qml

@@ -754,7 +754,7 @@ Item {
                                 width: parent.width
                                 height: 40
                                 radius: theme.radiusSm
-                                color: cfgHead.containsMouse ? theme.surfaceHover : theme.surfaceElevated
+                                color: cfgHead.containsMouse ? theme.surfaceElevatedHover : theme.surfaceElevated
                                 border.width: 1
                                 border.color: activeFocus ? theme.accent : theme.borderSubtle
                                 activeFocusOnTab: visible && enabled
@@ -978,7 +978,7 @@ Item {
                                     event.accepted = true
                                 }
                             }
-                            color: prevTa.containsMouse ? theme.surfaceHover : theme.surfaceElevated
+                            color: prevTa.containsMouse ? theme.surfaceElevatedHover : theme.surfaceElevated
                             QbzIcon {
                                 anchors.centerIn: parent
                                 width: 16
@@ -1016,7 +1016,7 @@ Item {
                                     event.accepted = true
                                 }
                             }
-                            color: nextTa.containsMouse ? theme.surfaceHover : theme.surfaceElevated
+                            color: nextTa.containsMouse ? theme.surfaceElevatedHover : theme.surfaceElevated
                             QbzIcon {
                                 anchors.centerIn: parent
                                 width: 16

crates/qbz-qt/qml/settings/LocalTabsConfigModal.qml

@@ -269,7 +269,7 @@ Item {
                 width: resetRow.width + 24
                 height: root.kioskHost ? 44 : 34
                 radius: theme.radiusSm
-                color: resetArea.containsMouse ? theme.surfaceHover : theme.surfaceElevated
+                color: resetArea.containsMouse ? theme.surfaceElevatedHover : theme.surfaceElevated
                 border.width: 1
                 border.color: activeFocus ? theme.accent : theme.borderSubtle
                 activeFocusOnTab: root.opened

crates/qbz-qt/qml/settings/MigrationSetupModal.qml

@@ -221,7 +221,7 @@ Item {
                         width: body.width
                         height: 92
                         radius: theme.radiusMd
-                        color: selected ? theme.surfaceHover : theme.surfaceElevated
+                        color: selected ? theme.surfaceElevatedHover : theme.surfaceElevated
                         border.width: selected ? 2 : 1
                         border.color: selected ? theme.accent : theme.borderSubtle