feat: add workspace rename dialog (#1429)

* feat: add workspace rename dialog

- Adds a modal dialog to rename the current workspace
- Supports both Niri (via IPC socket) and Hyprland (via hyprctl dispatch)
- Default keybinding: Ctrl+Shift+R to open the dialog
- Pre-fills with current workspace name
- Allows setting empty name to reset to default

* refactor: wrap WorkspaceRenameModal in LazyLoader

Reduces memory footprint when the modal is not in use.

quickshell/Services/DMSService.qml

@@ -737,4 +737,10 @@ Singleton {
             if (callback) callback(response);
         });
     }
+
+    function renameWorkspace(name, callback) {
+        sendRequest("extworkspace.renameWorkspace", {
+            "name": name
+        }, callback);
+    }
 }