feat(ui): redesign landing page and update styling

Overhaul landing page design with updated CSS, Tailwind config, and
i18n translations across all supported languages.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

assets/i18n/de.json

@@ -224,7 +224,13 @@
     "documentation": "Dokumentation",
     "api_reference": "API-Referenz",
     "support": "Support",
-    "copyright": "2026 CERTifAI. Alle Rechte vorbehalten."
+    "copyright": "2026 CERTifAI. Alle Rechte vorbehalten.",
+    "pill_gdpr": "DSGVO-Nativ",
+    "pill_self_hosted": "Selbst gehostet",
+    "pill_eu": "EU-Souveraen",
+    "preview_models": "Aktive Modelle",
+    "preview_tokens": "Tokens / Monat",
+    "preview_spend": "Gesamtausgaben"
   },
   "article": {
     "read_original": "Originalartikel lesen",

assets/i18n/en.json

@@ -224,7 +224,13 @@
     "documentation": "Documentation",
     "api_reference": "API Reference",
     "support": "Support",
-    "copyright": "2026 CERTifAI. All rights reserved."
+    "copyright": "2026 CERTifAI. All rights reserved.",
+    "pill_gdpr": "GDPR Native",
+    "pill_self_hosted": "Self-Hosted",
+    "pill_eu": "EU Sovereign",
+    "preview_models": "Active Models",
+    "preview_tokens": "Tokens / Month",
+    "preview_spend": "Total Spend"
   },
   "article": {
     "read_original": "Read original article",

assets/i18n/es.json

@@ -224,7 +224,13 @@
     "documentation": "Documentacion",
     "api_reference": "Referencia API",
     "support": "Soporte",
-    "copyright": "2026 CERTifAI. Todos los derechos reservados."
+    "copyright": "2026 CERTifAI. Todos los derechos reservados.",
+    "pill_gdpr": "RGPD Nativo",
+    "pill_self_hosted": "Autoalojado",
+    "pill_eu": "Soberania UE",
+    "preview_models": "Modelos Activos",
+    "preview_tokens": "Tokens / Mes",
+    "preview_spend": "Gasto Total"
   },
   "article": {
     "read_original": "Leer articulo original",

assets/i18n/fr.json

@@ -224,7 +224,13 @@
     "documentation": "Documentation",
     "api_reference": "Reference API",
     "support": "Support",
-    "copyright": "2026 CERTifAI. Tous droits reserves."
+    "copyright": "2026 CERTifAI. Tous droits reserves.",
+    "pill_gdpr": "RGPD Natif",
+    "pill_self_hosted": "Auto-heberge",
+    "pill_eu": "Souverainete UE",
+    "preview_models": "Modeles Actifs",
+    "preview_tokens": "Tokens / Mois",
+    "preview_spend": "Depenses Totales"
   },
   "article": {
     "read_original": "Lire l'article original",

assets/i18n/pt.json

@@ -224,7 +224,13 @@
     "documentation": "Documentacao",
     "api_reference": "Referencia API",
     "support": "Suporte",
-    "copyright": "2026 CERTifAI. Todos os direitos reservados."
+    "copyright": "2026 CERTifAI. Todos os direitos reservados.",
+    "pill_gdpr": "RGPD Nativo",
+    "pill_self_hosted": "Auto-Alojado",
+    "pill_eu": "Soberania UE",
+    "preview_models": "Modelos Ativos",
+    "preview_tokens": "Tokens / Mes",
+    "preview_spend": "Gasto Total"
   },
   "article": {
     "read_original": "Ler artigo original",