wiki: add Carbon Design System icons (2673) + pictograms (1000)

- 2673 SVG icons from @carbon/icons v11.82.0 (~2.5 MB)
- 1000 SVG pictograms from Carbon Design System (~2.0 MB)
- Updated 00-overview.md with asset structure and category listing

All icons: 32x32, fill: currentColor, optimized SVG
All pictograms: 24x24, fill: currentColor, SVG

assets/icons/carbon/add-child-node.svg

@@ -0,0 +1 @@
+<svg id="icon" width="32" height="32" viewBox="0 0 32 32"> <path d="M10,20v-8.1c2.28-.46,4-2.48,4-4.9,0-2.76-2.24-5-5-5s-5,2.24-5,5c0,2.41,1.72,4.43,4,4.9v8.1c0,3.31,2.69,6,6,6h1v-2h-1c-2.21,0-4-1.79-4-4ZM6,7c0-1.65,1.35-3,3-3s3,1.35,3,3-1.35,3-3,3-3-1.35-3-3ZM28,24v2h-4v4h-2v-4h-4v-2h4v-4h2v4h4Z"/> </svg>