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/join-node.svg

@@ -0,0 +1 @@
+<svg id="icon" width="32" height="32" viewBox="0 0 32 32"> <rect class="cls-2" x="2" y="9" width="4" height="2"/> <rect class="cls-2" x="2" y="21" width="4" height="2"/> <polygon class="cls-2" points="25 11 23.5859 12.4141 26.1719 15 18 15 18 4 12 4 12 9 8 9 8 11 12 11 12 21 8 21 8 23 12 23 12 28 18 28 18 17 26.1719 17 23.5859 19.5859 25 21 30 16 25 11"/> </svg>