feat(analytics): implement total transparency suite and SEO metadata standardization

- Added global ScrollDepthTracker (25%, 50%, 75%, 100%)
- Implemented ProductEngagementTracker for deep product analytics
- Added field-level tracking to ContactForm and RequestQuoteForm
- Standardized SEO metadata (canonical, alternates, x-default) across all routes
- Created reusable TrackedLink and TrackedButton components for server components
- Fixed 'useAnalytics' hook error in Footer.tsx by adding 'use client'

app/[locale]/products/page.tsx

@@ -4,9 +4,9 @@ import { Badge, Button, Card, Container, Heading, Section } from '@/components/u
 import { getTranslations, setRequestLocale } from 'next-intl/server';
 import { Metadata } from 'next';
 import Image from 'next/image';
-import Link from 'next/link';
 import { mapFileSlugToTranslated } from '@/lib/slugs';
 import { SITE_URL } from '@/lib/schema';
+import TrackedLink from '@/components/analytics/TrackedLink';
 
 interface ProductsPageProps {
   params: Promise<{
@@ -23,11 +23,11 @@ export async function generateMetadata({ params }: ProductsPageProps): Promise<M
     title,
     description,
     alternates: {
-      canonical: `/${locale}/${await mapFileSlugToTranslated('products', locale)}`,
+      canonical: `${SITE_URL}/${locale}/${await mapFileSlugToTranslated('products', locale)}`,
       languages: {
-        de: `/de/${await mapFileSlugToTranslated('products', 'de')}`,
-        en: `/en/${await mapFileSlugToTranslated('products', 'en')}`,
-        'x-default': `/en/${await mapFileSlugToTranslated('products', 'en')}`,
+        de: `${SITE_URL}/de/${await mapFileSlugToTranslated('products', 'de')}`,
+        en: `${SITE_URL}/en/${await mapFileSlugToTranslated('products', 'en')}`,
+        'x-default': `${SITE_URL}/en/${await mapFileSlugToTranslated('products', 'en')}`,
       },
     },
     openGraph: {
@@ -135,7 +135,15 @@ export default async function ProductsPage({ params }: ProductsPageProps) {
           <div className="grid grid-cols-1 md:grid-cols-2 gap-6 md:gap-8 lg:gap-12">
             {categories.map((category, idx) => (
               <Reveal key={idx} delay={idx * 100}>
-                <Link key={idx} href={category.href} className="group block">
+                <TrackedLink
+                  key={idx}
+                  href={category.href}
+                  className="group block"
+                  eventProperties={{
+                    category_title: category.title,
+                    location: 'products_index',
+                  }}
+                >
                   <Card className="h-full border-none shadow-sm hover:shadow-2xl transition-all duration-500 rounded-[24px] md:rounded-[48px] overflow-hidden bg-white active:scale-[0.98]">
                     <div className="relative h-[200px] md:h-[400px] overflow-hidden">
                       <Image
@@ -195,7 +203,7 @@ export default async function ProductsPage({ params }: ProductsPageProps) {
                       </div>
                     </div>
                   </Card>
-                </Link>
+                </TrackedLink>
               </Reveal>
             ))}
           </div>