refactor: eliminate hardcoded locale comparisons for antifragility

Created centralized helpers:
- src/lib/i18n/pageMetadata.ts: All page metadata (titles, descriptions, alt text)
- src/lib/i18n/productText.ts: Product-specific translated text (shortDescription, benefits)
- src/lib/i18n/metadata.ts: Helper functions for locale handling

Updated all pages to use centralized metadata:
- Homepage: Uses getPageMetadata for title, description, productionAlt
- Products page: Uses getPageMetadata
- Product detail: Uses getPageMetadata + getTranslatedShortDescription/getTranslatedBenefits
- About page: Uses getPageMetadata

ProductDetail component now uses:
- getTranslatedShortDescription() instead of locale comparison
- getTranslatedBenefits() instead of locale comparison

All user-facing text now goes through translation files or centralized helpers.
Adding a new language now requires only:
1. Add to SUPPORTED_LOCALES in locales.ts
2. Add LOCALE_CONFIG entry
3. Add entries to pageMetadata.ts and productText.ts
4. Add translation keys to message files

src/app/[locale]/about/page.tsx

@@ -1,6 +1,8 @@
 import { getTranslations, setRequestLocale } from "next-intl/server";
 import Header from "@/components/layout/Header";
 import Footer from "@/components/layout/Footer";
+import { getPageMetadata } from "@/lib/i18n/pageMetadata";
+import { isValidLocale, DEFAULT_LOCALE, type Locale } from "@/lib/i18n/locales";
 
 interface AboutPageProps {
   params: Promise<{ locale: string }>;
@@ -8,19 +10,19 @@ interface AboutPageProps {
 
 export async function generateMetadata({ params }: AboutPageProps) {
   const { locale } = await params;
+  const validLocale = isValidLocale(locale) ? locale : DEFAULT_LOCALE;
+  const metadata = getPageMetadata(validLocale as Locale);
   return {
-    title: locale === "sr" 
-      ? "O nama - ManoonOils"
-      : "About - ManoonOils",
-    description: locale === "sr"
-      ? "Saznajte više o ManoonOils - naša priča, misija i posvećenost prirodnoj lepoti."
-      : "Learn more about ManoonOils - our story, mission, and commitment to natural beauty.",
+    title: metadata.about.title,
+    description: metadata.about.description,
   };
 }
 
 export default async function AboutPage({ params }: AboutPageProps) {
   const { locale } = await params;
-  setRequestLocale(locale);
+  const validLocale = isValidLocale(locale) ? locale : DEFAULT_LOCALE;
+  const metadata = getPageMetadata(validLocale as Locale);
+  setRequestLocale(validLocale);
   const t = await getTranslations("About");
 
   return (
@@ -43,7 +45,7 @@ export default async function AboutPage({ params }: AboutPageProps) {
         <div className="relative h-[400px] md:h-[500px] overflow-hidden">
           <img
             src="https://images.unsplash.com/photo-1608571423902-eed4a5ad8108?q=80&w=2000&auto=format&fit=crop"
-            alt={locale === "sr" ? "Proizvodnja prirodnih ulja" : "Natural oils production"}
+            alt={metadata.productionAlt}
             className="w-full h-full object-cover"
           />
           <div className="absolute inset-0 bg-black/20" />