Add RedfishEndpoint controller scaffold

[spyroot]

Summary

• add a read-only RedfishEndpoint CRD status schema for BMC power, health, temperature, and poll timestamp
• add a Python controller scaffold that reads through redfish_ctl.api and updates status only
• add offline tests for CRD shape, status summarization, corpus-backed polling, and handler status patching

Verification

• python -m pytest -q tests/test_k8s_controller.py -> 5 passed in 1.15s
• python -m pytest -q tests/test_api_facade.py tests/test_k8s_mock_bmc_server.py -> 8 passed in 1.69s
• python -m pytest -q -> 795 passed, 57 skipped in 27.93s
• ruff check k8s/controller/redfish_endpoint_controller.py tests/test_k8s_controller.py -> All checks passed!