feat(theme): revise Polarized to classic green/teal dark palette

frontend/src/lib/__tests__/theme.test.ts

@@ -53,7 +53,7 @@ describe('custom themes', () => {
     expect(opt.isRounded).toBe(true);
   });
 
-  it('supports polarized and suri built-in purple dark themes', () => {
+  it('supports polarized and suri built-in dark themes', () => {
     setActiveTheme('polarized');
     expect(getActiveTheme()).toBe('polarized');
     expect(document.documentElement.getAttribute('data-theme')).toBe('polarized');