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>

themes/dark/theme.json

@@ -0,0 +1,13 @@
+{
+  "name": "KDC Dark",
+  "colors": {
+    "surface.background": "#0B0D12",
+    "surface.subtle":     "#12151B",
+    "surface.muted":      "#1B1F27",
+    "text.default":       "#F7F8FA",
+    "text.muted":         "#B8BDC9",
+    "text.inverse":       "#111827",
+    "border.default":     "#2A2F3A",
+    "border.strong":      "#3A4150"
+  }
+}