💩(frontend) introduce an official footer

Based on Florian's feedbacks, this is mandatory as the project is
getting attention.

Bad code, needs a refactor.

src/frontend/src/stores/layout.ts

@@ -3,10 +3,12 @@ import { PanelId } from '@/features/rooms/livekit/hooks/useSidePanel'
 
 type State = {
   showHeader: boolean
+  showFooter: boolean
   activePanelId: PanelId | null
 }
 
 export const layoutStore = proxy<State>({
   showHeader: false,
+  showFooter: false,
   activePanelId: null,
 })