feat: add design system handoff to feat/design-system branch

Adds colors_and_type.css token system, fonts (Lexend, Instrument Serif Italic,
JetBrains Mono, Atkinson Hyperlegible Next, OpenDyslexic), SVG assets (wordmark,
waveform mark, grain), HTML preview spec cards, UI kit, and SKILL.md reference
under src/design-system/. Foundation for applying the new Kon visual identity.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/assets/grain.svg

@@ -0,0 +1,4 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 200 200" width="200" height="200" preserveAspectRatio="none">
+  <filter id="n"><feTurbulence type="fractalNoise" baseFrequency="0.9" numOctaves="2" stitchTiles="stitch"></feTurbulence><feColorMatrix values="0 0 0 0 1  0 0 0 0 1  0 0 0 0 1  0 0 0 0.5 0"></feColorMatrix></filter>
+  <rect width="100%" height="100%" filter="url(#n)"></rect>
+</svg>

src/assets/waveform-mark.svg

@@ -0,0 +1,8 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 64 64" width="64" height="64">
+  <rect width="64" height="64" rx="14" fill="#1b1a17"></rect>
+  <g transform="translate(32 32)">
+    <rect x="-14" y="-10" width="5" height="20" rx="2.5" fill="#e8a87c" opacity="0.75"></rect>
+    <rect x="-4" y="-17" width="5" height="34" rx="2.5" fill="#e8a87c"></rect>
+    <rect x="6" y="-6" width="5" height="12" rx="2.5" fill="#e8a87c" opacity="0.5"></rect>
+  </g>
+</svg>

src/assets/wordmark.svg

@@ -0,0 +1,5 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 240 80" width="240" height="80">
+  <text x="12" y="54" font-family="&#39;Instrument Serif&#39;, Georgia, serif" font-style="italic" font-weight="400" font-size="48" fill="#e8a87c" letter-spacing="-0.01em">Kon</text>
+  <text x="92" y="46" font-family="&#39;Instrument Serif&#39;, Georgia, serif" font-size="28" fill="#e8a87c">ක</text>
+  <text x="12" y="70" font-family="&#39;Lexend&#39;, sans-serif" font-size="9" fill="#716b60" letter-spacing="1.4" text-transform="uppercase" style="text-transform:uppercase">THINK OUT LOUD</text>
+</svg>