refactor: add selected language signal

src/app/services/language-manager.ts

@@ -1,4 +1,4 @@
-import { inject, Injectable } from '@angular/core';
+import { inject, Injectable, signal } from '@angular/core';
 import { STRINGS_INJECTOR } from '../app.config';
 import { Language } from '../types/Language.type';
 
@@ -8,9 +8,12 @@ import { Language } from '../types/Language.type';
 export class LanguageManager {
   private readonly stringsDictionary = inject(STRINGS_INJECTOR);
 
+  private readonly selectedLanguage = signal<Language>('en');
+  readonly selectedLanguage$ = this.selectedLanguage.asReadonly();
   strings = this.stringsDictionary.en;
 
   setLanguage(language: Language) {
+    this.selectedLanguage.set(language);
     this.strings = this.stringsDictionary[language];
   }
 }