refactor: route localStorage access through shared LocalStorageService

Sprint 2 high-priority cleanup: cart/language/location services called
localStorage directly, bypassing the try/catch safety and core/<domain>
pattern used elsewhere (e.g. ProjectEditorDraftStorageService). New
core/storage/LocalStorageService centralizes get/set/remove and JSON
helpers with private-mode/quota error handling, reused across all three.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

src/app/core/storage/local-storage.service.ts

@@ -0,0 +1,53 @@
+import { Injectable } from '@angular/core';
+
+/**
+ * Safe wrapper around window.localStorage — swallows quota/private-mode
+ * errors instead of throwing, so callers don't each need their own try/catch.
+ */
+@Injectable({ providedIn: 'root' })
+export class LocalStorageService {
+  getItem(key: string): string | null {
+    try {
+      return typeof localStorage !== 'undefined' ? localStorage.getItem(key) : null;
+    } catch {
+      return null;
+    }
+  }
+
+  setItem(key: string, value: string): void {
+    try {
+      if (typeof localStorage !== 'undefined') {
+        localStorage.setItem(key, value);
+      }
+    } catch {
+      // storage unavailable (private mode / quota) - value simply won't persist
+    }
+  }
+
+  removeItem(key: string): void {
+    try {
+      if (typeof localStorage !== 'undefined') {
+        localStorage.removeItem(key);
+      }
+    } catch {
+      // ignore
+    }
+  }
+
+  getJSON<T>(key: string): T | null {
+    const raw = this.getItem(key);
+    if (!raw) {
+      return null;
+    }
+    try {
+      return JSON.parse(raw) as T;
+    } catch {
+      this.removeItem(key);
+      return null;
+    }
+  }
+
+  setJSON<T>(key: string, value: T): void {
+    this.setItem(key, JSON.stringify(value));
+  }
+}

src/app/services/cart.service.ts

@@ -2,6 +2,7 @@ import { Injectable, signal, computed, effect, Injector } from '@angular/core';
 import { DeliveryOption, CartItem } from '../models';
 import { getDiscountedPrice } from '../utils/item.utils';
 import { normalizeDeliveryOption, normalizeOptionalNumber } from '../utils/normalization.utils';
+import { LocalStorageService } from '../core/storage/local-storage.service';
 import type { } from '../types/telegram.types';
 
 type CartVariant = { colour?: string; size?: string; price?: number; currency?: string };
@@ -49,7 +50,7 @@ export class CartService {
       && items.some(item => (item.deliveryOptions?.length ?? 0) > 0 || item.selectedDelivery != null);
   });
 
-  constructor(private injector: Injector) {
+  constructor(private injector: Injector, private readonly storage: LocalStorageService) {
     this.loadCart();
     
     // Auto-save whenever cart changes (skip the initial empty state)
@@ -133,7 +134,7 @@ export class CartService {
     const data = JSON.stringify(items);
 
     // Always save to localStorage
-    localStorage.setItem(this.STORAGE_KEY, data);
+    this.storage.setItem(this.STORAGE_KEY, data);
 
     // Also save to Telegram CloudStorage if available
     if (this.isTelegram) {
@@ -167,7 +168,7 @@ export class CartService {
   }
 
   private loadFromLocalStorage(): void {
-    const stored = localStorage.getItem(this.STORAGE_KEY);
+    const stored = this.storage.getItem(this.STORAGE_KEY);
     if (stored) {
       this.parseAndSetCart(stored);
     }

src/app/services/language.service.ts

@@ -1,5 +1,6 @@
 import { Injectable, signal } from '@angular/core';
 import { Router } from '@angular/router';
+import { LocalStorageService } from '../core/storage/local-storage.service';
 
 export interface Language {
   code: string;
@@ -38,14 +39,14 @@ export class LanguageService {
   currentLanguage = this.currentLanguageSignal.asReadonly();
   currentCurrency = this.currentCurrencySignal.asReadonly();
 
-  constructor(private router: Router) {
+  constructor(private router: Router, private readonly storage: LocalStorageService) {
     // Load saved language from localStorage
-    const savedLang = localStorage.getItem('selectedLanguage');
+    const savedLang = this.storage.getItem('selectedLanguage');
     if (savedLang && this.languages.find(l => l.code === savedLang && l.enabled)) {
       this.currentLanguageSignal.set(savedLang);
     }
 
-    const savedCurrency = localStorage.getItem('selectedCurrency');
+    const savedCurrency = this.storage.getItem('selectedCurrency');
     if (savedCurrency && this.currencies.find(c => c.code === savedCurrency)) {
       this.currentCurrencySignal.set(savedCurrency);
     }
@@ -55,7 +56,7 @@ export class LanguageService {
     const lang = this.languages.find(l => l.code === langCode);
     if (lang && lang.enabled) {
       this.currentLanguageSignal.set(langCode);
-      localStorage.setItem('selectedLanguage', langCode);
+      this.storage.setItem('selectedLanguage', langCode);
     }
   }
 
@@ -63,7 +64,7 @@ export class LanguageService {
     const currency = this.currencies.find(c => c.code === code);
     if (currency) {
       this.currentCurrencySignal.set(code);
-      localStorage.setItem('selectedCurrency', code);
+      this.storage.setItem('selectedCurrency', code);
     }
   }
 

src/app/services/location.service.ts

@@ -2,6 +2,7 @@ import { Injectable, signal, computed } from '@angular/core';
 import { HttpClient } from '@angular/common/http';
 import { Region, GeoIpResponse } from '../models/location.model';
 import { ApiConfigService } from '../core/config/api-config.service';
+import { LocalStorageService } from '../core/storage/local-storage.service';
 
 const STORAGE_KEY = 'selected_region';
 
@@ -28,7 +29,8 @@ export class LocationService {
 
   constructor(
     private readonly http: HttpClient,
-    private readonly apiConfig: ApiConfigService
+    private readonly apiConfig: ApiConfigService,
+    private readonly storage: LocalStorageService
   ) {
     this.loadRegions();
     this.restoreFromStorage();
@@ -55,13 +57,13 @@ export class LocationService {
   /** Set region by user choice */
   setRegion(region: Region): void {
     this.regionSignal.set(region);
-    localStorage.setItem(STORAGE_KEY, JSON.stringify(region));
+    this.storage.setJSON(STORAGE_KEY, region);
   }
 
   /** Clear region (go global) */
   clearRegion(): void {
     this.regionSignal.set(null);
-    localStorage.removeItem(STORAGE_KEY);
+    this.storage.removeItem(STORAGE_KEY);
   }
 
   /** Auto-detect user location via IP geolocation */
@@ -111,14 +113,9 @@ export class LocationService {
 
   /** Restore previously selected region from storage */
   private restoreFromStorage(): void {
-    try {
-      const stored = localStorage.getItem(STORAGE_KEY);
-      if (stored) {
-        const region: Region = JSON.parse(stored);
-        this.regionSignal.set(region);
-      }
-    } catch {
-      localStorage.removeItem(STORAGE_KEY);
+    const region = this.storage.getJSON<Region>(STORAGE_KEY);
+    if (region) {
+      this.regionSignal.set(region);
     }
   }