changed locales from .ts to .json,

configured i18n-ally,
upgrade APIlite and regenerated BackendAPI.ts,
fixed successMessage value

frontend/src/locales/en.json

@@ -0,0 +1,41 @@
+{
+	"app": {
+		"name": "Nutrio",
+		"slogan": "Meal planning, nutrition, and daily totals in one place."
+	},
+	"auth": {
+		"title": "Sign in",
+		"subtitle": "Use your email and password. If the account does not exist, it will be created automatically.",
+		"emailLabel": "Email",
+		"emailPlaceholder": "e.g. name{'@'}domain.com",
+		"passwordLabel": "Password",
+		"passwordPlaceholder": "Enter password",
+		"submit": "Sign in",
+		"submitting": "Processing...",
+		"helper": "After successful sign-in, the token will be stored in your browser.",
+		"tokenSaved": "Token was saved.",
+		"successLoggedIn": "Sign-in was successful.",
+		"successAutoRegistered": "Account did not exist, it was created and the user is now signed in.",
+		"themeToggle": "Toggle mode",
+		"languageLabel": "Language",
+		"showPassword": "Show password",
+		"hidePassword": "Hide password",
+		"errors": {
+			"invalidEmail": "Enter a valid email address.",
+			"passwordRequired": "Enter password.",
+			"invalidCredentials": "Email or password is incorrect.",
+			"loginFailed": "Sign-in failed. Please try again."
+		}
+	},
+	"theme": {
+		"light": "Light mode",
+		"dark": "Dark mode"
+	},
+	"locale": {
+		"sk": "Slovak",
+		"cs": "Czech",
+		"en": "English",
+		"es": "Spanish",
+		"de": "German"
+	}
+}