chore: initial scaffold of KDC Design System

Initial repository scaffold:
- design.md (google-labs-code/design.md format) as canonical token + guidelines source
- brand assets, foundations, tokens (W3C-style JSON)
- 12 component primitives, each with labeled anatomy.svg and spec README
- light / dark / high-contrast themes, web/mobile/email/print/presentation templates
- docs (getting started, principles, a11y, voice & tone, contributing)
- runnable web example, token build script stub, CI placeholder

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

components/dropdowns/README.md

@@ -0,0 +1,25 @@
+# Dropdowns
+
+Specification for the **dropdowns** primitive.
+
+## Anatomy
+TODO — drop `anatomy.svg` next to this file.
+
+## Variants
+- default
+- (list per-component variants)
+
+## States
+default · hover · focus-visible · active/pressed · disabled · loading
+
+## Tokens used
+See `design.md` → `components.dropdowns.*`.
+
+## Accessibility
+- All interactive instances are keyboard-reachable.
+- Focus state has ≥ 3:1 contrast against its background.
+- Pair color with an icon or text to convey meaning.
+
+## Do / Don't
+- ✅ Use the canonical token references.
+- ❌ Don't hardcode colors, sizes, or radii.