fix: tag coloring code duplications cleand up

tests/renderer/utils/color.test.ts

@@ -0,0 +1,19 @@
+import { describe, it, expect } from 'vitest';
+import { getContrastColor } from '../../../src/renderer/utils/color';
+
+describe('getContrastColor', () => {
+  it('should return black text for light 6-char colors', () => {
+    expect(getContrastColor('#ffffff')).toBe('#000000');
+    expect(getContrastColor('fef3c7')).toBe('#000000');
+  });
+
+  it('should return white text for dark 6-char colors', () => {
+    expect(getContrastColor('#000000')).toBe('#ffffff');
+    expect(getContrastColor('1f2937')).toBe('#ffffff');
+  });
+
+  it('should support 3-char hex colors', () => {
+    expect(getContrastColor('#abc')).toBe('#000000');
+    expect(getContrastColor('333')).toBe('#ffffff');
+  });
+});