Update README and localization files to remove "self-hosted" references

- Revised the README.md to simplify the description of Nexumi.
- Updated layout.tsx to reflect the change in the bot's description.
- Modified German and English localization files to remove "self-hosted" from the bot's description and terms of service.

landingpage/assets/nexumi-logo.svg

@@ -0,0 +1,37 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512" role="img" aria-label="Nexumi logo">
+  <defs>
+    <linearGradient id="bg" x1="0" y1="0" x2="1" y2="1">
+      <stop offset="0" stop-color="#181C2B"/>
+      <stop offset="1" stop-color="#0C0E15"/>
+    </linearGradient>
+    <linearGradient id="mark" x1="0" y1="1" x2="1" y2="0">
+      <stop offset="0" stop-color="#6366F1"/>
+      <stop offset="1" stop-color="#8B5CF6"/>
+    </linearGradient>
+  </defs>
+
+  <!-- App-Icon-Grundflaeche -->
+  <rect width="512" height="512" rx="116" fill="url(#bg)"/>
+  <rect x="1.5" y="1.5" width="509" height="509" rx="114.5" fill="none" stroke="#FFFFFF" stroke-opacity="0.06" stroke-width="3"/>
+
+  <!-- Glow: gestaffelte Deckkraft statt Filter, rendersicher -->
+  <g fill="none" stroke="url(#mark)" stroke-linecap="round" stroke-linejoin="round">
+    <path d="M170 362 V150 L342 362 V150" stroke-width="78" stroke-opacity="0.10"/>
+    <path d="M170 362 V150 L342 362 V150" stroke-width="52" stroke-opacity="0.16"/>
+  </g>
+
+  <!-- Kanten des N -->
+  <path d="M170 362 V150 L342 362 V150" fill="none" stroke="url(#mark)"
+        stroke-width="30" stroke-linecap="round" stroke-linejoin="round"/>
+
+  <!-- Knoten -->
+  <g fill="url(#mark)">
+    <circle cx="170" cy="150" r="34"/>
+    <circle cx="170" cy="362" r="34"/>
+    <circle cx="342" cy="362" r="34"/>
+    <circle cx="342" cy="150" r="34"/>
+  </g>
+
+  <!-- Aktiver Knoten oben rechts -->
+  <circle cx="342" cy="150" r="14" fill="#C7D2FE"/>
+</svg>