feat(desktop): fold calc into combi and rebind the power menu (task 0024)

Move the calc mode into the combi prompt so math results show inline
alongside apps, leaving emoji as the one tab-away mode. Rebind the
power menu from Super+Escape to Super+Shift+X, pairing it with lock on
Super+X. Shorten the layer fade-in so the launcher appears quicker.

modules/desktop/hyprland/hyprland.nix

@@ -98,6 +98,9 @@ in
           animation = [
             "windows, 1, 3, ease"
             "fade, 1, 3, ease"
+            # Layer surfaces like the launcher appear quicker than windows.
+            "layersIn, 1, 2, ease"
+            "fadeLayersIn, 1, 2, ease"
             "workspaces, 1, 3, ease"
             "border, 1, 3, ease"
           ];