Refactor context and provider structure for improved organization and maintainability

- Removed individual context files for Auth, Flyers, MasterItems, Modal, UserData, and their respective hooks.
- Introduced centralized provider files for each context, encapsulating logic and state management.
- Updated imports across the application to reflect the new structure, ensuring all hooks and contexts are correctly referenced.
- Enhanced the AppProviders component to streamline the wrapping of all context providers in the application.
- Improved type definitions and context management for better type safety and clarity.

src/contexts/FlyersContext.ts

@@ -0,0 +1,15 @@
+// src/contexts/FlyersContext.ts
+import { createContext } from 'react';
+import type { Flyer } from '../types';
+
+export interface FlyersContextType {
+  flyers: Flyer[];
+  isLoadingFlyers: boolean;
+  flyersError: Error | null;
+  fetchNextFlyersPage: () => void;
+  hasNextFlyersPage: boolean;
+  isRefetchingFlyers: boolean;
+  refetchFlyers: () => void;
+}
+
+export const FlyersContext = createContext<FlyersContextType | undefined>(undefined);