feat(i18n): integrate internationalization for game pages

- Added translation support for various game-related texts in the home, daily, infinite, login, and profile pages.
- Replaced hardcoded French strings with translation keys using the `$t` function.
- Updated titles, descriptions, and button texts to enhance localization.

src/lib/i18n/index.ts

@@ -0,0 +1,51 @@
+import { writable, derived } from 'svelte/store';
+import type { Writable, Readable } from 'svelte/store';
+
+import en from './en.json';
+import fr from './fr.json';
+
+type Messages = typeof en;
+
+const translations: Record<string, Messages> = { en, fr };
+
+// Get initial language
+function getInitialLanguage(): string {
+	if (typeof window !== 'undefined') {
+		const stored = localStorage.getItem('language');
+		if (stored && stored in translations) {
+			return stored;
+		}
+		const browserLang = navigator.language.split('-')[0];
+		if (browserLang in translations) {
+			return browserLang;
+		}
+	}
+	return 'en';
+}
+
+// Create writable store for the current language
+export const language: Writable<string> = writable(getInitialLanguage());
+
+// Create derived store for the current messages
+export const t: Readable<Messages> = derived(language, ($language) => {
+	return translations[$language] || translations['en'];
+});
+
+export function setLanguage(lang: string) {
+	if (lang in translations) {
+		if (typeof window !== 'undefined') {
+			localStorage.setItem('language', lang);
+		}
+		language.set(lang);
+	}
+}
+
+export function getLanguage(): string {
+	let currentLang = 'en';
+	language.subscribe((lang) => {
+		currentLang = lang;
+	})();
+	return currentLang;
+}
+
+export const availableLanguages = Object.keys(translations);