fix(ci): increase realistic YAML validation threshold for CI

- Increase realistic validation threshold from 200ms to 300ms avg
- Increase max threshold from 400ms to 500ms
- CI shows 260ms avg vs 100ms local
- Still catches 2x+ slowdown regressions

Author: edeno

src/__tests__/baselines/performance.baseline.test.js

@@ -108,9 +108,10 @@ describe('BASELINE: Performance Metrics', () => {
         `📊 Validation (8 electrode groups): avg=${result.avg.toFixed(2)}ms, min=${result.min.toFixed(2)}ms, max=${result.max.toFixed(2)}ms`
       );
 
-      // Threshold: Realistic session should validate in < 200ms on average
-      expect(result.avg).toBeLessThan(200);
-      expect(result.max).toBeLessThan(400);
+      // Threshold: Realistic session should validate in < 300ms on average
+      // CI environments are slower than local (local: ~100ms, CI: ~260ms)
+      expect(result.avg).toBeLessThan(300);
+      expect(result.max).toBeLessThan(500);
     });
 
     it('validates complete YAML with all features', () => {