docs: update documentation links and expand Q2-Q3 2026 milestone plan

- Fix broken documentation links in intro.md to point to correct agent documentation paths
- Update agent marketplace, swarm, and development links to use consolidated getting-started.md
- Expand Q2-Q3 2026 milestone plan from "OpenClaw Agent Economic Model & Scalability" to "Global Marketplace Expansion"
- Add comprehensive global infrastructure scaling strategy with multi-region deployment
- Include cross-chain agent economics

docs/8_development/contributing.md

@@ -501,9 +501,9 @@ mentorship = await builder.become_mentor({
 
 ## Next Steps
 
-- [Development Setup Guide](setup.md) - Configure your development environment
-- [API Reference](api-reference.md) - Detailed technical documentation
-- [Best Practices](best-practices.md) - Guidelines for high-quality contributions
-- [Community Guidelines](community.md) - Collaboration and communication standards
+- [Development Setup Guide](2_setup.md) - Configure your development environment
+- [API Reference](../6_architecture/3_coordinator-api.md) - Detailed technical documentation
+- [Best Practices](../9_security/1_security-cleanup-guide.md) - Guidelines for high-quality contributions
+- [Community Guidelines](3_contributing.md) - Collaboration and communication standards
 
-Ready to start building? [Set Up Development Environment →](setup.md)
+Ready to start building? [Set Up Development Environment →](2_setup.md)