feat: improve SEO with locale-specific metadata, structured data, and keywords

- Add locale-specific title/description for DE and EN homepage
- Expand keywords with local SEO terms (Webentwicklung Osnabrück, Informatik, etc.)
- Add WebSite schema and enhance Person schema with knowsAbout, alternateName
- Add hreflang alternates for DE/EN
- Update projects page with locale-specific metadata
- Keep visible titles short, move SEO terms to description/structured data

app/[locale]/page.tsx

@@ -2,6 +2,19 @@ import type { Metadata } from "next";
 import HomePageServer from "../_ui/HomePageServer";
 import { getLanguageAlternates, toAbsoluteUrl } from "@/lib/seo";
 
+const localeMetadata: Record<string, { title: string; description: string }> = {
+  de: {
+    title: "Dennis Konkol – Webentwickler Osnabrück",
+    description:
+      "Dennis Konkol – Software Engineer & Webentwickler in Osnabrück. Webentwicklung, Fullstack-Apps, Docker, Next.js, Flutter. Projekte ansehen und Kontakt aufnehmen.",
+  },
+  en: {
+    title: "Dennis Konkol – Web Developer Osnabrück",
+    description:
+      "Dennis Konkol – Software Engineer & Web Developer in Osnabrück, Germany. Web development, fullstack apps, Docker, Next.js, Flutter.",
+  },
+};
+
 export async function generateMetadata({
   params,
 }: {
@@ -9,7 +22,10 @@ export async function generateMetadata({
 }): Promise<Metadata> {
   const { locale } = await params;
   const languages = getLanguageAlternates({ pathWithoutLocale: "" });
+  const meta = localeMetadata[locale] ?? localeMetadata.en;
   return {
+    title: meta.title,
+    description: meta.description,
     alternates: {
       canonical: toAbsoluteUrl(`/${locale}`),
       languages,

app/[locale]/projects/page.tsx

@@ -13,7 +13,12 @@ export async function generateMetadata({
 }): Promise<Metadata> {
   const { locale } = await params;
   const languages = getLanguageAlternates({ pathWithoutLocale: "projects" });
+  const isDe = locale === "de";
   return {
+    title: isDe ? "Projekte – Dennis Konkol" : "Projects – Dennis Konkol",
+    description: isDe
+      ? "Webentwicklung, Fullstack-Apps und Mobile-Projekte von Dennis Konkol. Next.js, Flutter, Docker und mehr – Osnabrück."
+      : "Web development, fullstack apps and mobile projects by Dennis Konkol. Next.js, Flutter, Docker and more – Osnabrück.",
     alternates: {
       canonical: toAbsoluteUrl(`/${locale}/projects`),
       languages,