Add Mylder brand design system with warm amber accent

- Implement comprehensive design system with OKLCH colors
- Add warm stone neutrals replacing cold zinc grays
- Add amber brand color for CTAs and accents
- Update typography to Plus Jakarta Sans + JetBrains Mono
- Add brand variants to Button and Badge components
- Add utility classes: glass, shadow-brand, text-gradient-brand
- Update all pages to use semantic design tokens
- Add design system documentation

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/components/ui/button.tsx

@@ -10,15 +10,24 @@ const buttonVariants = cva(
     variants: {
       variant: {
         default: "bg-primary text-primary-foreground hover:bg-primary/90",
+        brand:
+          "bg-brand text-brand-foreground hover:bg-brand/90 shadow-brand hover:shadow-brand-lg transition-shadow",
         destructive:
           "bg-destructive text-white hover:bg-destructive/90 focus-visible:ring-destructive/20 dark:focus-visible:ring-destructive/40 dark:bg-destructive/60",
+        success:
+          "bg-success text-success-foreground hover:bg-success/90",
         outline:
           "border bg-background shadow-xs hover:bg-accent hover:text-accent-foreground dark:bg-input/30 dark:border-input dark:hover:bg-input/50",
+        "outline-brand":
+          "border-brand/30 bg-brand/5 text-brand hover:bg-brand/10 hover:border-brand/50",
         secondary:
           "bg-secondary text-secondary-foreground hover:bg-secondary/80",
         ghost:
           "hover:bg-accent hover:text-accent-foreground dark:hover:bg-accent/50",
+        "ghost-brand":
+          "text-brand hover:bg-brand/10 hover:text-brand",
         link: "text-primary underline-offset-4 hover:underline",
+        "link-brand": "text-brand underline-offset-4 hover:underline",
       },
       size: {
         default: "h-9 px-4 py-2 has-[>svg]:px-3",