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/design-system/SKILL.md

@@ -0,0 +1,26 @@
+---
+name: kon-design
+description: Use this skill to generate well-branded interfaces and assets for Kon (by CORBEL), either for production or throwaway prototypes/mocks/etc. Contains essential design guidelines, colors, type, fonts, assets, and UI kit components for prototyping.
+user-invocable: true
+---
+
+Read the README.md file within this skill, and explore the other available files.
+
+If creating visual artifacts (slides, mocks, throwaway prototypes, etc), copy assets out and create static HTML files for the user to view. If working on production code, you can copy assets and read the rules here to become an expert in designing with this brand.
+
+If the user invokes this skill without any other guidance, ask them what they want to build or design, ask some questions, and act as an expert designer who outputs HTML artifacts _or_ production code, depending on the need.
+
+## Essence — non-negotiable
+- **Clarity without friction.** Every decision measured against it.
+- **Neurodivergent-first.** No streak-shaming, no guilt, no red urgency, no auto-play.
+- Warm brutalism — Barbican / Muji / Nujabes. Not San Francisco SaaS.
+- Amber is always meaningful. Never decorative.
+- Sentence case. No emoji. Never italic for body.
+
+## Files
+- `colors_and_type.css` — import this for all tokens + semantic type.
+- `README.md` — full brand + content + visual foundations.
+- `assets/` — logos, glyph, grain, icon samples.
+- `ui_kits/kon-app/` — component recreations of the desktop app.
+- `preview/` — spec cards (swatches, specimens, components).
+- `kon-source/` — ground-truth Svelte source from the Kon repo.