Strengthen article with comprehensive competitive positioning and customer success metrics

Major enhancements based on Pulumi IaC Competitive Position document:
- Add quantifiable customer results (Unity 80%, Snowflake 90%, Starburst 112x improvements)
- Enhance competitive analysis for Terraform, OpenTofu, AWS CDK with balanced strengths/limitations
- Integrate 'Software engineering for infrastructure' messaging throughout
- Add comprehensive migration guidance with proven timelines (Atlassian 2-day migration)
- Strengthen FAQ with pain point-focused answers and success stories
- Update introduction and conclusion with 'Real Languages, Real Tools, Real Results' brand alignment
- Add dedicated migration strategies section with best practices
- Fix markdown list formatting to pass linting requirements

Transforms article from basic tool overview to competitive intelligence-driven guide.

Author: asafashirov