feat: Implement price info card component and product categories with grid view

- Added `price-info-card.component` to display total amount, tax, and payable amount.
- Integrated price masking directive for formatted price display.
- Created `categories.component` to list product categories with loading skeletons.
- Implemented `grid-view.component` for displaying products in a grid layout.
- Enhanced `products.component` to manage category selection and product display.
- Introduced new models for product categories and stock responses.
- Updated `main.service.ts` to fetch product categories and stock data.
- Refactored `POSStore` to manage state for products, categories, and order items.
- Added utility functions for price formatting and number normalization.
- Included placeholder images for product and logo.

src/app/modules/pos/services/main.service.ts

@@ -0,0 +1,34 @@
+import { IPaginatedResponse } from '@/core/models/service.model';
+import { HttpClient } from '@angular/common/http';
+import { Injectable } from '@angular/core';
+import { Observable } from 'rxjs';
+import { POS_API_ROUTES } from '../constants';
+import {
+  IPosInfoRawResponse,
+  IPosInfoResponse,
+  IPosProductCategoriesRawResponse,
+  IPosProductCategoriesResponse,
+  IPosStockRawResponse,
+  IPosStockResponse,
+} from '../models';
+
+@Injectable({ providedIn: 'root' })
+export class PosService {
+  constructor(private http: HttpClient) {}
+
+  private apiRoutes = POS_API_ROUTES;
+
+  getInfo(): Observable<IPosInfoResponse> {
+    return this.http.get<IPosInfoRawResponse>(this.apiRoutes.info());
+  }
+
+  getStock(): Observable<IPaginatedResponse<IPosStockResponse>> {
+    return this.http.get<IPaginatedResponse<IPosStockRawResponse>>(this.apiRoutes.stock());
+  }
+
+  getCategories(): Observable<IPaginatedResponse<IPosProductCategoriesResponse>> {
+    return this.http.get<IPaginatedResponse<IPosProductCategoriesRawResponse>>(
+      this.apiRoutes.productCategories(),
+    );
+  }
+}