Refresh docs, skills, and production runtime assets

[arpan404]

Summary

• Expanded the public docs with deployment, migration, performance, and troubleshooting guides.
• Updated the docs navigation, landing pages, examples index, and environment variable reference for production usage.
• Refreshed agent skill assets and searchable documentation indexes under skills/.
• Tightened and extended runtime behavior across LLM, memory, queues, tools, A2A, and security-related code paths.
• Added and updated tests to cover the new cache, timeout middleware, Redis pooling, A2A auth, and tooling changes.

Testing

• Not run.
• Expected validation checks: PYTHONPATH=src pytest -q.
• Expected targeted checks for affected areas: PYTHONPATH=src pytest -q tests/llms/test_timeout_middleware.py, PYTHONPATH=src pytest -q tests/llms/test_redis_pool.py, PYTHONPATH=src pytest -q tests/agents/test_a2a_auth_and_host.py.