ci: GitHub Actions pipelines for validation, install test, and release

docs: comprehensive documentation with tutorials, references, and Mermaid diagrams

feat: agent lifecycle commands (create, deploy, status, logs, test, templates)

feat: infrastructure commands (config, bootstrap, teardown)

feat: /leia main entry point with NL routing

feat: schema references for astromesh agent, nexus API, WhatsApp, and orchestration patterns

feat: 5 specialized subagents (interpreter, architect, operator, tester, doctor)

feat: 6 business-vertical agent templates (support, restaurant, ecommerce, scheduler, sales, onboarding)

feat: initialize astromesh-leia plugin scaffold