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/volume-down.svg

@@ -0,0 +1 @@
+<svg id="icon" viewBox="0 0 32 32"><title>volume--down</title><path d="M25.1,10.66,23.58,12a6,6,0,0,1-.18,7.94l1.47,1.36a8,8,0,0,0,.23-10.59Z"/><path d="M20,30a1,1,0,0,1-.71-.3L11.67,22H5a1,1,0,0,1-1-1H4V11a1,1,0,0,1,1-1h6.67l7.62-7.7a1,1,0,0,1,1.41,0A1,1,0,0,1,21,3V29A1,1,0,0,1,20,30ZM6,20h6a1.17,1.17,0,0,1,.79.3L19,26.57V5.43L12.79,11.7A1.17,1.17,0,0,1,12,12H6Z"/></svg>