Add MCP container icons (128x128 PNG + SVG sources)

icons/esphome-mcp.svg

@@ -0,0 +1,7 @@
+<svg xmlns="http://www.w3.org/2000/svg" width="128" height="128" viewBox="0 0 128 128">
+  <rect x="24" y="16" width="80" height="80" rx="16" fill="#3D6A8C"/>
+  <text x="64" y="72" font-family="Arial, sans-serif" font-size="30" font-weight="bold" fill="#FFFFFF" text-anchor="middle">eS</text>
+  <circle cx="88" cy="38" r="8" fill="#FFD166"/>
+  <rect x="44" y="96" width="40" height="18" rx="4" fill="#3D6A8C"/>
+  <text x="64" y="109" font-family="Arial, sans-serif" font-size="11" font-weight="bold" fill="#FFFFFF" text-anchor="middle">MCP</text>
+</svg>