Add named keyboard binding modes (#32)

Add named keyboard shortcut maps with an Escape exit and a panel indicator. Keep press/release ownership across transitions, validate remapped Escape keys, and cancel stale repeats and focus previews.

Give the indicator ownership of the panel while a mode is active. Close popovers, collapse Morph, and keep Live Activities data current without resizing the hidden panel. Document configuration and transition behavior.

Validation: 1,519 workspace Rust tests passed; 70 Python tests passed. Workspace build, formatting, Clippy, and Settings configuration validation passed. Opt-in native desktop checks were not rerun because Weston is absent.

Related: #5.

compositor/src/config/bindings/index.rs

@@ -2,6 +2,7 @@ use super::*;
 
 /// Immutable bindings and their keyboard index are replaced together on reload.
 /// The ordered slice remains available for gestures and the shortcut guide.
+#[derive(Clone)]
 pub(crate) struct BindingSet {
     ordered: Vec<Binding>,
     keyboard: HashMap<BindingIdentity, usize>,
@@ -32,7 +33,7 @@ impl std::ops::Deref for BindingSet {
 }
 
 impl BindingSet {
-    pub(crate) fn action_for_key(
+    pub(crate) fn binding_for_key(
         &self,
         keycode: Keycode,
         symbols: &[u32],
@@ -40,7 +41,7 @@ impl BindingSet {
         ctrl: bool,
         alt: bool,
         shift: bool,
-    ) -> Option<&BindingAction> {
+    ) -> Option<&Binding> {
         let modifiers = BindingModifiers { logo, ctrl, alt, shift };
         let physical = self.keyboard.get(&BindingIdentity {
             modifiers,
@@ -60,7 +61,21 @@ impl BindingSet {
             .into_iter()
             .chain(symbolic)
             .min()
-            .map(|&index| &self.ordered[index].action)
+            .map(|&index| &self.ordered[index])
+    }
+
+    #[cfg(test)]
+    pub(crate) fn action_for_key(
+        &self,
+        keycode: Keycode,
+        symbols: &[u32],
+        logo: bool,
+        ctrl: bool,
+        alt: bool,
+        shift: bool,
+    ) -> Option<&BindingAction> {
+        self.binding_for_key(keycode, symbols, logo, ctrl, alt, shift)
+            .map(|binding| &binding.action)
     }
 }