fix: resolve HTML hierarchy, accessibility and PDF link issues

- Fix heading level skip in ContactContent success state (H3 -> H2)
- Clean up deprecated iframe attributes in ContactContent
- Add aria-label to footer logo link for WCAG compliance
- Rename PDF assets to hyphenated filenames to fix link checks
- Update AGB page with new PDF link format

components/ContactContent.tsx

@@ -162,13 +162,8 @@ export default function Contact() {
                 <div className="w-full h-[300px] rounded-[2.5rem] overflow-hidden border border-white/10 shadow-sm grayscale hover:grayscale-0 transition-all duration-700 relative group">
                   <div className="absolute inset-0 border-2 border-accent/0 group-hover:border-accent/20 transition-all duration-500 z-10 pointer-events-none rounded-[2.5rem]" />
                   <iframe
-                    width="100%"
-                    height="100%"
-                    frameBorder="0"
-                    scrolling="no"
-                    marginHeight={0}
-                    marginWidth={0}
-                    title="Location Map"
+                    className="w-full h-full border-0"
+                    title={t("info.mapTitle") || "Location Map"}
                     src="https://www.openstreetmap.org/export/embed.html?bbox=9.445,48.815,9.465,48.825&layer=mapnik&marker=48.8198,9.4552"
                   ></iframe>
                 </div>
@@ -185,9 +180,9 @@ export default function Contact() {
                     <div className="w-20 h-20 rounded-full bg-accent/10 text-accent flex items-center justify-center mx-auto mb-8">
                       <CheckCircle size={40} />
                     </div>
-                    <h3 className="text-3xl font-bold text-primary mb-4">
+                    <h2 className="text-3xl font-bold text-primary mb-4">
                       {t("form.successTitle")}
-                    </h3>
+                    </h2>
                     <p className="text-slate-600 text-lg mb-10">
                       {t("form.successMessage")}
                     </p>

components/Layout.tsx

@@ -184,7 +184,11 @@ const Layout = ({ children }: { children: React.ReactNode }) => {
           <div className="container-custom relative z-10">
             <div className="grid grid-cols-1 md:grid-cols-2 lg:grid-cols-4 gap-10 md:gap-12 mb-12 md:mb-16">
               <div className="lg:col-span-2">
-                <Link href="/" className="inline-block mb-6 md:mb-8 group">
+                <Link
+                  href="/"
+                  className="inline-block mb-6 md:mb-8 group"
+                  aria-label={t("nav.home")}
+                >
                   <div className="relative h-16 md:h-20 w-48 brightness-0 invert opacity-80 group-hover:opacity-100 transition-opacity">
                     <Image
                       src="/assets/logo.png"

components/StatusModal.tsx

@@ -75,9 +75,9 @@ export const StatusModal = ({
                   )}
                 </div>
 
-                <h3 className="text-3xl font-extrabold text-primary mb-4 leading-tight">
+                <h2 className="text-3xl font-extrabold text-primary mb-4 leading-tight">
                   {title}
-                </h3>
+                </h2>
                 <p className="text-slate-600 text-lg mb-10 leading-relaxed">
                   {message}
                 </p>