Add CrewAI integration helpers

[SaiSandeepKantareddy]

Summary

• add optional CrewAI integration helpers to the Python SDK
• add a backend-agnostic SochDB knowledge store that works with embedded collections or gRPC collections
• expose CrewAI search and remember tools backed by SochDB
• add both embedded and hosted remote CrewAI examples, plus README and examples index updates
• add a remote preflight mode so teams can validate the hosted SochDB path before wiring LLM credentials

Included

• SochDBKnowledgeStore
• SochDBSearchTool and SochDBRememberTool
• create_crewai_tools(...) helper
• optional crewai extra in pyproject.toml
• examples/28_crewai_knowledge_tools.py
• examples/29_crewai_remote_tools.py
• tests/test_crewai_integration.py
• README and examples/README updates

Notes

• CrewAI remains an optional dependency
• the integration supports both embedded collections and gRPC collections
• examples/29_crewai_remote_tools.py supports SOCHDB_CREWAI_SKIP_KICKOFF=1 for remote storage/search preflight without LLM credentials

Validation

• python3 -m py_compile examples/28_crewai_knowledge_tools.py examples/29_crewai_remote_tools.py tests/test_crewai_integration.py
• git diff --check
• pytest collection for the CrewAI test still depends on grpc being installed in the local environment

[SaiSandeepKantareddy]

Verified the new remote CrewAI path from an isolated venv.\n\nExample added: examples/29_crewai_remote_tools.py\n\nUseful commands:\n\nbash\n# Remote SochDB preflight without LLM credentials\nSOCHDB_CREWAI_SKIP_KICKOFF=1 python -u examples/29_crewai_remote_tools.py\n\n# Full CrewAI kickoff once OPENAI_API_KEY is configured\nOPENAI_API_KEY=... python -u examples/29_crewai_remote_tools.py\n\n\nWhat I verified in the isolated env:\n- hosted gRPC collection creation worked\n- document insert worked\n- remote search worked\n- the preflight example returned grounded hits from the hosted store\n\nSo the remote SochDB side is confirmed working; the only extra requirement for the full CrewAI kickoff is model-provider credentials.