chore: weaviate cli and python version increases

[CariZa]

Summary

• Bump weaviate-client >=4.21.0 -> >=4.23.0. Older clients raise ValueError: 'INTEGRATING' is not a valid ReplicateOperationState, breaking get/query replications
• python_requires >=3.9 -> >=3.10, drop 3.9 classifier, add 3.13. The client has required 3.10+ since 4.21.0, so 3.9 already could not install
• Mark max_workers and alive_nodes_checking_frequency deprecated — removed server-side in v1.37.3. Still parsed and sent, so older servers are unaffected; warns only on v1.37.3+
• Update --help and skill docs, which led with the deprecated max_workers in every example
• Add 11 unit tests

[orca-security-eu]

Orca Security Scan Summary

Status	Check	Issues by priority
Passed	Infrastructure as Code	0   0   0   0	View in Orca
Passed	SAST	0   0   0   0	View in Orca
Passed	Secrets	0   0   0   0	View in Orca
Passed	Vulnerabilities	0   0   0   0	View in Orca