docs(readme): rework header with logo, badges, nav links

docs/logo/icon-inline.svg

@@ -0,0 +1,27 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 64 82" width="64" height="82" fill="none">
+  <defs>
+    <radialGradient id="bg-glow" cx="50%" cy="35%" r="55%">
+      <stop offset="0%" stop-color="#00d4ff" stop-opacity="0.08"/>
+      <stop offset="100%" stop-color="#0d1117" stop-opacity="0"/>
+    </radialGradient>
+    <filter id="node-glow">
+      <feGaussianBlur stdDeviation="1.5" result="blur"/>
+      <feMerge><feMergeNode in="blur"/><feMergeNode in="SourceGraphic"/></feMerge>
+    </filter>
+  </defs>
+  <circle cx="32" cy="32" r="32" fill="#0d1117"/>
+  <circle cx="32" cy="32" r="32" fill="url(#bg-glow)"/>
+  <path d="M32 11 L53 30 L48 30 L48 53 L16 53 L16 30 L11 30 Z"
+        fill="#161b22" stroke="#00d4ff" stroke-width="1.5" stroke-linejoin="round"/>
+  <line x1="16" y1="30" x2="48" y2="30" stroke="#00d4ff" stroke-width="0.5" opacity="0.25"/>
+  <rect x="27" y="40" width="10" height="13" rx="1.5"
+        fill="#0d1117" stroke="#00d4ff" stroke-width="1" opacity="0.9"/>
+  <line x1="32" y1="23" x2="32" y2="30" stroke="#a855f7" stroke-width="1.2" opacity="0.7" stroke-linecap="round"/>
+  <line x1="21" y1="38" x2="29" y2="33" stroke="#39d353" stroke-width="1.2" opacity="0.7" stroke-linecap="round"/>
+  <line x1="43" y1="38" x2="35" y2="33" stroke="#39d353" stroke-width="1.2" opacity="0.7" stroke-linecap="round"/>
+  <circle cx="32" cy="33" r="5" fill="#00d4ff" opacity="0.12"/>
+  <circle cx="32" cy="33" r="3" fill="#00d4ff" filter="url(#node-glow)"/>
+  <circle cx="21" cy="38" r="2.5" fill="#39d353" filter="url(#node-glow)"/>
+  <circle cx="43" cy="38" r="2.5" fill="#39d353" filter="url(#node-glow)"/>
+  <circle cx="32" cy="23" r="2" fill="#a855f7" filter="url(#node-glow)"/>
+</svg>