feat(portfolio): replace skills section with about section and skills marquee

- Remove old skills data and components
- Add new about section with personal introduction and stats
- Implement animated skills marquee component
- Update navigation to reflect new section structure

src/pages/index.astro

@@ -2,7 +2,8 @@
 import Layout from "@/layouts/Layout.astro";
 import GlassHeader from "@/components/GlassHeader";
 import HeroSection from "@/components/HeroSection";
-import SkillsSection from "@/components/SkillsSection";
+import AboutSection from "@/components/AboutSection";
+import SkillsMarquee from "@/components/SkillsMarquee";
 import ProjectsSection from "@/components/ProjectsSection";
 import Footer from "@/components/Footer";
 import { useTranslations, type Lang } from "@/i18n/utils";
@@ -17,7 +18,8 @@ const pageTitle = t('page.home.title');
   <GlassHeader lang={lang} client:only="react" />
   <main class="min-h-screen">
     <HeroSection lang={lang} client:only="react" />
-    <SkillsSection lang={lang} client:only="react" />
+    <SkillsMarquee lang={lang} client:only="react" />
+    <AboutSection lang={lang} client:only="react" />
     <ProjectsSection lang={lang} client:only="react" />
   </main>
   <Footer lang={lang} client:only="react" />