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');

frontend/src/lib/theme.ts

@@ -70,13 +70,13 @@ export const AVAILABLE_THEMES: ThemeOption[] = [
   },
   {
     id: 'polarized',
-    name: 'Polarized (Ultraviolet)',
-    subtitle: 'Tiefdunkles Obsidian mit elektrischem Violett (0px)',
+    name: 'Polarized (Emerald / Teal)',
+    subtitle: 'Tiefdunkles Obsidian mit elektrischem Türkis/Grün (0px)',
     file: 'src/themes/theme-polarized.css',
-    previewBg: '#0d0b14',
-    previewPanel: '#151221',
-    previewAccent: '#a855f7',
-    previewText: '#f5f3ff',
+    previewBg: '#090e11',
+    previewPanel: '#10181c',
+    previewAccent: '#14b8a6',
+    previewText: '#f0fdfa',
     isRounded: false,
   },
   {