design: two-color palette — rename all tokens to --cream / --blue

Replace ochre-clay, carbon-black, burnt-oxide, slate-indigo with clean
two-color system: --cream (#f4f0e8) and --blue (#041cf3). Update every
component, utility class, and test assertion.

src/shared/ui/Section/ui/Section.test.tsx

@@ -18,17 +18,13 @@ describe('Section', () => {
   });
 
   describe('background variants', () => {
-    it('defaults to ochre background', () => {
+    it('defaults to cream background', () => {
       const { container } = render(<Section>x</Section>);
-      expect(container.querySelector('section')).toHaveClass('bg-ochre-clay', 'text-carbon-black');
+      expect(container.querySelector('section')).toHaveClass('bg-cream', 'text-blue');
     });
-    it('applies slate background', () => {
-      const { container } = render(<Section background="slate">x</Section>);
-      expect(container.querySelector('section')).toHaveClass('bg-slate-indigo', 'text-ochre-clay');
-    });
-    it('applies white background', () => {
-      const { container } = render(<Section background="white">x</Section>);
-      expect(container.querySelector('section')).toHaveClass('bg-white', 'text-carbon-black');
+    it('applies blue background', () => {
+      const { container } = render(<Section background="blue">x</Section>);
+      expect(container.querySelector('section')).toHaveClass('bg-blue', 'text-cream');
     });
   });
 

src/shared/ui/Section/ui/Section.tsx

@@ -1,7 +1,7 @@
 import type { ReactNode } from 'react';
 import { cn } from '$shared/lib';
 
-export type SectionBackground = 'ochre' | 'slate' | 'white';
+export type SectionBackground = 'cream' | 'blue';
 export type ContainerSize = 'default' | 'wide' | 'ultra-wide';
 
 interface SectionProps {
@@ -11,7 +11,7 @@ interface SectionProps {
   children: ReactNode;
   /**
    * Background color variant
-   * @default 'ochre'
+   * @default 'cream'
    */
   background?: SectionBackground;
   /**
@@ -26,15 +26,14 @@ interface SectionProps {
 }
 
 const BACKGROUNDS: Record<SectionBackground, string> = {
-  ochre: 'bg-ochre-clay text-carbon-black',
-  slate: 'bg-slate-indigo text-ochre-clay',
-  white: 'bg-white text-carbon-black',
+  cream: 'bg-cream text-blue',
+  blue: 'bg-blue text-cream',
 };
 
 /**
  * Full-width page section with background and optional borders.
  */
-export function Section({ children, background = 'ochre', bordered = false, className }: SectionProps) {
+export function Section({ children, background = 'cream', bordered = false, className }: SectionProps) {
   return (
     <section className={cn(BACKGROUNDS[background], bordered && 'brutal-border-top brutal-border-bottom', className)}>
       {children}