feat: shared loading state + cleanup loading state management (#5835)

* feat: implement shared loading bar component and polished loading states across the app

* feat: align loading states + ensureQueryData changes

* fix: lint + bugs

* fix: skeleton for manage servers page

* fix: merge conflict fix

packages/ui/src/providers/index.ts

@@ -7,6 +7,7 @@ export * from './file-picker'
 export * from './hosting-purchase-intent'
 export * from './i18n'
 export * from './instance-import'
+export * from './loading-state'
 export * from './modal-behavior'
 export * from './page-context'
 export * from './popup-notifications'