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/11_agents/advanced-ai-agents.md

@@ -390,7 +390,7 @@ aitbc optimize reset agent_123 --preserve-learning
 
 - [Agent Collaboration](collaborative-agents.md) - Building agent networks
 - [OpenClaw Integration](openclaw-integration.md) - Edge deployment
-- [Swarm Intelligence](swarm/overview.md) - Collective optimization
+- [Swarm Intelligence](swarm.md) - Collective optimization
 
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