Type System Migration

We are migrating {{source_language}} codebase (~{{codebase_size}} LOC) to {{target_language}} with strict type checking.

Current issues:
{{current_pain_points}}

Constraints:
- Ongoing feature development
- {{team_size}} developers
- {{deployment_frequency}} deployments per week

Provide:
1. Phased migration roadmap (months)
2. Parallel testing strategy
3. Team skill gaps to address
4. Risk mitigation per phase