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/threshold.svg

@@ -0,0 +1 @@
+<svg id="icon" width="32" height="32" viewBox="0 0 32 32"> <path d="M26,4H6A2.0025,2.0025,0,0,0,4,6V26a2.0025,2.0025,0,0,0,2,2H26a2.0023,2.0023,0,0,0,2-2V6A2.0023,2.0023,0,0,0,26,4ZM6,6H26V16H24v2h2v2H24v2h2v2H24v2H22V24H20v2H18V24H16v2H14V24H12v2H10V24H8v2H6Z"/> <rect x="8" y="20" width="2" height="2"/> <rect x="12" y="20" width="2" height="2"/> <rect x="16" y="20" width="2" height="2"/> <rect x="20" y="20" width="2" height="2"/> <rect x="8" y="16" width="2" height="2"/> <rect x="16" y="16" width="2" height="2"/> <rect x="20" y="16" width="2" height="2"/> <rect x="20" y="12" width="2" height="2"/> <rect x="20" y="8" width="2" height="2"/> </svg>