Add display mode chooser and align screen-sharing styles

Open the four display modes from XF86Display or the external-monitor bar icon. Reuse output reconciliation and confirmation for manual layout changes, and notify the shell when monitor state changes.

Release backdrop locks before render-element queries to prevent blurred popups from freezing the compositor. Cover popup open, update and close with regression tests.

Share translucent card styles between display modes and capture sources, show focus rings during keyboard navigation, and align picker buttons, label sizing and footer spacing with system modals.

compositor/src/output_policy.rs

@@ -40,6 +40,7 @@ pub(crate) struct DesiredOutputConfiguration {
 pub(crate) struct ManualOverride {
     pub profile: Option<String>,
     pub internal: Option<bool>,
+    pub layout: Option<OutputLayout>,
     topology: Option<(BTreeSet<String>, bool)>,
 }
 
@@ -55,6 +56,7 @@ impl ManualOverride {
         if self.topology.as_ref().is_some_and(|old| old != &topology) {
             self.profile = None;
             self.internal = None;
+            self.layout = None;
         }
         if self.profile.as_ref().is_some_and(|name| {
             !profiles
@@ -134,7 +136,9 @@ pub(crate) fn select_profile(
                 })
                 .map(|(_, profile)| profile)
         });
-    let layout = selected.map_or(OutputLayout::Extend, |profile| profile.layout);
+    let layout = manual
+        .layout
+        .unwrap_or_else(|| selected.map_or(OutputLayout::Extend, |profile| profile.layout));
     let manage_lid = selected.is_none_or(|profile| profile.lid_policy == LidPolicy::DockOrSuspend);
     let external = monitors.iter().any(|monitor| monitor.usable && !monitor.internal);
     let mut outputs = monitors
@@ -149,6 +153,9 @@ pub(crate) fn select_profile(
                 })
                 .cloned()
                 .unwrap_or_else(|| defaults(monitor.identity.clone()));
+            if manual.layout.is_some() {
+                settings.enabled = true;
+            }
             settings.enabled &= monitor.usable;
             settings.enabled &= match layout {
                 OutputLayout::InternalOnly => monitor.internal,
@@ -465,6 +472,57 @@ mod tests {
         }
     }
 
+    #[test]
+    fn manual_layouts_reuse_profiles_and_expire_on_monitor_changes() {
+        let connected = [monitor("eDP-1", true), monitor("DP-1", false)];
+        let mut settings = defaults("DP-1".into());
+        settings.enabled = false;
+        settings.scale = 1.5;
+        let mut mobile = profile("mobile", &["eDP-1"], OutputLayout::InternalOnly);
+        mobile.outputs.push(settings);
+        let profiles = [mobile];
+        for layout in [
+            OutputLayout::InternalOnly,
+            OutputLayout::ExternalOnly,
+            OutputLayout::Extend,
+            OutputLayout::Mirror,
+        ] {
+            let mut manual = ManualOverride {
+                layout: Some(layout),
+                ..ManualOverride::default()
+            };
+            manual.observe(&connected, false, &profiles);
+            let desired = select_profile(&connected, false, &profiles, &manual);
+            assert_eq!(
+                desired.outputs[0].settings.enabled,
+                layout != OutputLayout::ExternalOnly
+            );
+            assert_eq!(
+                desired.outputs[1].settings.enabled,
+                layout != OutputLayout::InternalOnly
+            );
+            assert_eq!(
+                desired.outputs[1].settings.scale, 1.5,
+                "manual layout must preserve configured scale"
+            );
+            assert_eq!(
+                desired
+                    .outputs
+                    .iter()
+                    .filter(|output| output.mirror_source.is_some())
+                    .count(),
+                usize::from(layout == OutputLayout::Mirror)
+            );
+            manual.observe(&connected[..1], false, &profiles);
+            assert_eq!(manual.layout, None);
+            assert!(
+                select_profile(&connected[..1], false, &profiles, &manual).outputs[0]
+                    .settings
+                    .enabled
+            );
+        }
+    }
+
     #[test]
     fn specificity_and_config_order() {
         let monitors = [monitor("eDP-1", true), monitor("DP-1", false)];