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'

components/Header.tsx

@@ -8,10 +8,13 @@ import { usePathname } from 'next/navigation';
 import { Button } from './ui';
 import { useEffect, useState } from 'react';
 import { cn } from './ui';
+import { useAnalytics } from './analytics/useAnalytics';
+import { AnalyticsEvents } from './analytics/analytics-events';
 
 export default function Header() {
   const t = useTranslations('Navigation');
   const pathname = usePathname();
+  const { trackEvent } = useAnalytics();
   const [isScrolled, setIsScrolled] = useState(false);
   const [isMobileMenuOpen, setIsMobileMenuOpen] = useState(false);
 
@@ -79,7 +82,15 @@ export default function Header() {
             animate={{ scale: 1, opacity: 1 }}
             transition={{ duration: 0.6, ease: 'easeOut', delay: 0.1 }}
           >
-            <Link href={`/${currentLocale}`}>
+            <Link
+              href={`/${currentLocale}`}
+              onClick={() =>
+                trackEvent(AnalyticsEvents.BUTTON_CLICK, {
+                  target: 'home_logo',
+                  location: 'header',
+                })
+              }
+            >
               <Image
                 src={logoSrc}
                 alt={t('home')}
@@ -109,7 +120,14 @@ export default function Header() {
                 <motion.div key={item.href} variants={navLinkVariants}>
                   <Link
                     href={`/${currentLocale}${item.href === '/' ? '' : item.href}`}
-                    onClick={() => setIsMobileMenuOpen(false)}
+                    onClick={() => {
+                      setIsMobileMenuOpen(false);
+                      trackEvent(AnalyticsEvents.LINK_CLICK, {
+                        label: item.label,
+                        href: item.href,
+                        location: 'header_nav',
+                      });
+                    }}
                     className={cn(
                       textColorClass,
                       'hover:text-accent font-bold transition-all duration-500 text-base md:text-lg tracking-tight relative group inline-block hover:-translate-y-0.5',
@@ -139,6 +157,14 @@ export default function Header() {
                 >
                   <Link
                     href={getPathForLocale('en')}
+                    onClick={() =>
+                      trackEvent(AnalyticsEvents.TOGGLE_SWITCH, {
+                        type: 'language',
+                        from: currentLocale,
+                        to: 'en',
+                        location: 'header',
+                      })
+                    }
                     className={`hover:text-accent transition-colors flex items-center gap-2 touch-target ${currentLocale === 'en' ? 'text-accent' : 'opacity-60'}`}
                   >
                     EN
@@ -157,6 +183,14 @@ export default function Header() {
                 >
                   <Link
                     href={getPathForLocale('de')}
+                    onClick={() =>
+                      trackEvent(AnalyticsEvents.TOGGLE_SWITCH, {
+                        type: 'language',
+                        from: currentLocale,
+                        to: 'de',
+                        location: 'header',
+                      })
+                    }
                     className={`hover:text-accent transition-colors flex items-center gap-2 touch-target ${currentLocale === 'de' ? 'text-accent' : 'opacity-60'}`}
                   >
                     DE
@@ -174,6 +208,12 @@ export default function Header() {
                   variant="white"
                   size="md"
                   className="px-8 shadow-xl"
+                  onClick={() =>
+                    trackEvent(AnalyticsEvents.BUTTON_CLICK, {
+                      label: t('contact'),
+                      location: 'header_cta',
+                    })
+                  }
                 >
                   {t('contact')}
                 </Button>
@@ -196,7 +236,14 @@ export default function Header() {
                 damping: 20,
                 delay: 0.5,
               }}
-              onClick={() => setIsMobileMenuOpen(!isMobileMenuOpen)}
+              onClick={() => {
+                const newState = !isMobileMenuOpen;
+                setIsMobileMenuOpen(newState);
+                trackEvent(AnalyticsEvents.BUTTON_CLICK, {
+                  type: 'mobile_menu',
+                  action: newState ? 'open' : 'close',
+                });
+              }}
             >
               <motion.svg
                 className="w-7 h-7"
@@ -274,7 +321,14 @@ export default function Header() {
               >
                 <Link
                   href={`/${currentLocale}${item.href === '/' ? '' : item.href}`}
-                  onClick={() => setIsMobileMenuOpen(false)}
+                  onClick={() => {
+                    setIsMobileMenuOpen(false);
+                    trackEvent(AnalyticsEvents.LINK_CLICK, {
+                      label: item.label,
+                      href: item.href,
+                      location: 'mobile_menu',
+                    });
+                  }}
                   className="text-2xl md:text-3xl font-extrabold text-white hover:text-accent transition-all transform block py-4"
                 >
                   {item.label}