Branding: logo + social preview (matching the main ComfyPeeper style)

- assets/icon.svg + icon.png: two-node workflow mark with a green "send"
  arrow, on a dark brand-bordered square
- assets/social-preview.svg + social-preview.png (1280×640): mirrors the
  main repo's banner, lens holding a two-way arrow (→ ComfyUI, ← Discord)
- README shows the banner; pyproject Icon points at icon.png

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

assets/icon.svg

@@ -0,0 +1,25 @@
+<svg xmlns="http://www.w3.org/2000/svg" width="256" height="256" viewBox="0 0 256 256">
+  <defs>
+    <linearGradient id="bg" x1="0" y1="0" x2="1" y2="1">
+      <stop offset="0" stop-color="#15161a"/>
+      <stop offset="1" stop-color="#202127"/>
+    </linearGradient>
+    <radialGradient id="glow" cx="0.5" cy="0.42" r="0.6">
+      <stop offset="0" stop-color="#5865f2" stop-opacity="0.28"/>
+      <stop offset="1" stop-color="#5865f2" stop-opacity="0"/>
+    </radialGradient>
+  </defs>
+
+  <rect width="256" height="256" rx="56" fill="url(#bg)"/>
+  <rect width="256" height="256" rx="56" fill="url(#glow)"/>
+  <rect x="6" y="6" width="244" height="244" rx="50" fill="none" stroke="#5865f2" stroke-opacity="0.45" stroke-width="3"/>
+
+  <!-- two-node "workflow" glyph (ComfyPeeper mark) -->
+  <g fill="#5865f2" fill-opacity="0.14" stroke="#7c86ff" stroke-width="9" stroke-linecap="round" stroke-linejoin="round">
+    <rect x="62" y="60" width="60" height="60" rx="16"/>
+    <rect x="134" y="136" width="60" height="60" rx="16"/>
+    <path d="M92 120 V148 a16 16 0 0 0 16 16 H134" fill="none"/>
+  </g>
+  <!-- green "send" arrowhead flowing into the second node -->
+  <path d="M122 154 L140 166 L122 178 Z" fill="#43b581"/>
+</svg>