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/chevron-down.svg

@@ -0,0 +1,7 @@
+<!-- Generator: Adobe Illustrator 22.1.0, SVG Export Plug-In . SVG Version: 6.00 Build 0) -->
+<svg version="1.1" id="icon" x="0px" y="0px" viewBox="0 0 32 32" style="enable-background:new 0 0 32 32;" xml:space="preserve">
+<style type="text/css"> .st0{fill:none;}
+</style>
+<polygon points="16,22 6,12 7.4,10.6 16,19.2 24.6,10.6 26,12 "/>
+<rect id="_x3C_Transparent_Rectangle_x3E_" class="st0" width="32" height="32"/>
+</svg>