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/entities/experience/ui/ExperienceCard.test.tsx

@@ -37,10 +37,10 @@ describe('ExperienceCard', () => {
       expect(screen.getByRole('heading', { level: 4 })).toHaveTextContent('Senior Developer');
     });
 
-    it('period badge has brutal-border, bg-carbon-black, text-ochre-clay, text-sm', () => {
+    it('period badge has brutal-border, bg-blue, text-cream, text-sm', () => {
       render(<ExperienceCard {...DEFAULT_PROPS} />);
       const badge = screen.getByText('2021 – 2024');
-      expect(badge).toHaveClass('brutal-border', 'bg-carbon-black', 'text-ochre-clay', 'text-sm');
+      expect(badge).toHaveClass('brutal-border', 'bg-blue', 'text-cream', 'text-sm');
     });
 
     it('company paragraph has opacity-80', () => {

src/entities/experience/ui/ExperienceCard.tsx

@@ -34,7 +34,7 @@ export function ExperienceCard({ title, company, period, description, className
           <h4>{title}</h4>
           <p className="text-base opacity-80">{company}</p>
         </div>
-        <span className="brutal-border px-4 py-2 bg-carbon-black text-ochre-clay text-sm self-start">{period}</span>
+        <span className="brutal-border px-4 py-2 bg-blue text-cream text-sm self-start">{period}</span>
       </div>
       <p className="text-base max-w-[700px]">{description}</p>
     </Card>