feat: ExperienceCard stack field and Card subcomponent layout

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

@@ -6,6 +6,7 @@ const DEFAULT_PROPS = {
   company: 'Acme Corp',
   period: '2021 – 2024',
   description: 'Built scalable frontend systems.',
+  stack: [],
 };
 
 describe('ExperienceCard', () => {
@@ -32,9 +33,9 @@ describe('ExperienceCard', () => {
   });
 
   describe('structure', () => {
-    it('title is rendered as an h4', () => {
+    it('title is rendered as an h3', () => {
       render(<ExperienceCard {...DEFAULT_PROPS} />);
-      expect(screen.getByRole('heading', { level: 4 })).toHaveTextContent('Senior Developer');
+      expect(screen.getByRole('heading', { level: 3 })).toHaveTextContent('Senior Developer');
     });
 
     it('period badge has brutal-border, bg-blue, text-cream, text-sm', () => {
@@ -43,11 +44,11 @@ describe('ExperienceCard', () => {
       expect(badge).toHaveClass('brutal-border', 'bg-blue', 'text-cream', 'text-sm');
     });
 
-    it('company paragraph has opacity-80', () => {
+    it('company paragraph has opacity-60', () => {
       render(<ExperienceCard {...DEFAULT_PROPS} />);
       const company = screen.getByText('Acme Corp');
       expect(company.tagName).toBe('P');
-      expect(company).toHaveClass('opacity-80');
+      expect(company).toHaveClass('opacity-60');
     });
 
     it('description renders via RichText with rich-text class', () => {