NVIDIA cuOpt backend integration (service/SDK adapter)

[pesap]

Description

Add NVIDIA cuOpt support as an optional backend for large-scale optimization workflows.

Scope

• New backend adapter crate or module (likely service/SDK-oriented rather than pure in-process C API)
• Feature-gated integration for CLI and Python
• Normalize cuOpt solve results into Arco SolverStatus + solution structures
• Support auth/config for endpoint, token, timeout, and retries

Acceptance criteria

• Feature-gated build path compiles without cuOpt deps by default
• CLI can select cuOpt backend and run a small benchmark model
• Python exposes arco.CuOpt(...) when enabled
• Capability matrix includes cuOpt row
• Robust error mapping for auth/network/service failures
• Integration tests with mocked/stubbed cuOpt endpoint in CI
• Docs for setup (local/cloud), credentials, and limitations

Notes

• Confirm supported deployment mode (cloud API vs local SDK) and licensing constraints.
• Keep backend unavailable-path diagnostics actionable.