[SDK] Add hardware API support

[yaxan]

Summary

• Add create_hardware_instance(request) and delete_hardware_instance(hardware_instance_id) to CentMLClient, wrapping the hardware-instance endpoints added in platform PR https://github.com/CentML/platform/pull/3707.
• Implements https://github.com/CentML/platform/issues/3782. SDK only, no CLI support, as requested in the issue.

What changed

• centml/sdk/api.py: two thin delegating methods on CentMLClient, matching the existing create_job pattern:
  • create_hardware_instance(request: CreateHardwareInstanceRequest) -> HardwareInstanceResponse
  • delete_hardware_instance(hardware_instance_id: int) -> None
• tests/test_sdk_api.py: 3 unit tests (create, delete, and coverage for the existing get's .results extraction)
• examples/sdk/manage_hardware_instances.py: new Click example with list / create / delete subcommands.

Test plan

• pytest --sanity tests/test_sdk_api.py: 8 passed (3 new).
• Black --line-length 120 --
• Pylint (repo rcfile) 10.00/10 on changed files.
• manage_hardware_instances.py --help works for all subcommands.

Unit test	Asserts
`test_create_hardware_instance_	delegates tocreate_hardware_instance_hardware_instances_post with the request; returns the response
`test_delete_hardware_instance_	delegates todelete_hardware_instance_hardware_instances_hardware_instance_id_delete with the id
test_get_hardware_instances_returns_results	returns the .results payload, passes cluster_id through

[anandj91]

@codex review

[chatgpt-codex-connector]

Codex Review: Didn't find any major issues. 🎉

Reviewed commit: ec6d2819ed

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