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/triangle-down-outline.svg

@@ -0,0 +1 @@
+<svg id="icon" width="32" height="32" viewBox="0 0 32 32"> <path class="cls-2" d="m2.1245,4.4883l13.0195,23.9868c.1865.3438.5212.5249.856.5249.3345,0,.6689-.1812.8555-.5249L29.875,4.4883c.0862-.1582.1255-.3257.125-.4883-.0017-.5229-.4114-1-.9805-1H2.9802c-.5691,0-.9788.4771-.9802,1-.0005.1626.0386.3301.1245.4883Zm25.1985.5117l-11.323,20.8677L4.677,5h22.646Z"/> </svg>