feat: add async demo support and enhance template resolution

- Introduced async demo functionality in the README, allowing for asynchronous data preparation before rendering components.
- Updated WccDashboard, WccProperties, and WccSidebar to support Promise-based template factories.
- Implemented resolveTemplateFactory to handle both synchronous and asynchronous template results.
- Added tests for resolveTemplateFactory to ensure correct behavior for both sync and async templates.
- Updated pnpm workspace configuration.

ts_web/elements/wcc-properties.ts

@@ -1,5 +1,6 @@
 import { DeesElement, property, html, customElement, type TemplateResult, state } from '@design.estate/dees-element';
 import { WccDashboard } from './wcc-dashboard.js';
+import type { TTemplateFactory } from './wcctools.helpers.js';
 
 export type TPropertyType = 'String' | 'Number' | 'Boolean' | 'Object' | 'Enum' | 'Array';
 
@@ -20,7 +21,7 @@ export class WccProperties extends DeesElement {
   public dashboardRef: WccDashboard;
 
   @property()
-  public selectedItem: (() => TemplateResult) | DeesElement;
+  public selectedItem: TTemplateFactory | DeesElement;
 
   @property()
   public selectedViewport: TEnvironment = 'native';