style(quality): use pure black for Issue Categories chip labels

Changed text color from #1a1a1a to #000000 for maximum contrast
and readability on white backgrounds.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: aledlie

src/features/dashboard/components/CodeQualityPage.tsx

@@ -224,9 +224,9 @@ function CategoryBreakdown({ issuesByCategory, total }: {
                 fontWeight: 500,
                 fontSize: 'var(--font-size-small, 12px)',
                 borderColor: 'rgba(0, 0, 0, 0.23)',
-                color: '#1a1a1a',
+                color: '#000000',
                 '& .MuiChip-label': {
-                  color: '#1a1a1a',
+                  color: '#000000',
                 },
                 '& .MuiChip-icon': {
                   color: '#0066cc',