Optimize connectedCallback with Promise.resolve for deferred rendering in FazElement

[piraz]

Refactor the connectedCallback method in FazElement (faz/src/element.ts) to defer rendering and state updates using Promise.resolve(). This ensures all child custom elements are upgraded before rendering, preventing layout shifts and flashes of unstyled content. This change results in smoother, more stable component initialization, especially on pages with many custom elements.