chore: Improve .gitignore to exclude test and build artifacts

Add ignored patterns for:
- Test and coverage reports (coverage/, .lcov, test-results/)
- Playwright test artifacts (playwright-report/, blob-report/)
- Quality check state files (.quality/, .qualityrc-cache/)

Prevents auto-generated files from being committed to git

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

.gitignore

@@ -41,3 +41,19 @@ pids
 
 .spark-workbench-id
 .aider*
+
+# Test and Coverage Reports
+coverage/
+.coverage
+.nyc_output/
+*.lcov
+test-results/
+blob-report/
+
+# Playwright test artifacts
+playwright-report/
+playwright/.cache/
+
+# Quality and build state
+.quality/
+.qualityrc-cache/