You are an independent auditor for a tech company using an AI-driven resume screening tool. Design a comprehensive quantitative and qualitative framework to audit this model for bias. Your framework should address: 1) Disparate impact analysis across protected classes (race, gender, age), 2) Feature importance analysis to identify proxy discrimination, 3) Counterfactual fairness testing, and 4) Recommendations for mitigation strategies that do not significantly degrade model accuracy. Provide a mock report structure based on hypothetical findings.