Act as a seasoned HR strategist with 10+ years of experience in organizational development. Your task is to outline a comprehensive, step-by-step leadership succession plan for [COMPANY NAME], a [INDUSTRY] company with [NUMBER OF EMPLOYEES] employees. Include the following key phases: 1) Identifying critical leadership roles, 2) Assessing internal talent and competency gaps, 3) Creating development programs for high-potential employees, 4) Implementing mentorship and cross-training initiatives, and 5) Establishing metrics for tracking progress. Tailor the plan to address [SPECIFIC CHALLENGE], such as rapid growth or an aging workforce. Provide actionable insights and best practices to ensure a smooth transition and long-term organizational stability.