[cristim]

Summary

• Removes stale comment in commitmentopts.Validate that described Savings Plans as "not commitment-capable in our probe set" -- PR feat(commitmentopts): probe Savings Plans offerings live (closes #108) #569 added SavingsPlansProber to DefaultProbers, making that comment incorrect.
• Adds four Validate tests covering SP service keys (savings-plans-compute, -ec2instance, -sagemaker, -database) to close the coverage gap that the chunk-0 bucket-A verification flagged.

Precedence chain

probe snapshot present for service key -> reject invalid combos
service key absent from snapshot -> permissive fallback (plan type not offered in region)
ErrNoData (cold store / no AWS account) -> permissive fallback (never block saves)

What PR #569 left incomplete vs claimed

The probe code and DefaultProbers wiring were complete. The gap was:

1. A stale comment in Validate still implied SP was unprobed.
2. No tests exercised the Validate path with the real SP service keys, so the probe-first behavior was unverified.

The Validate logic itself was already correct post #569 -- Get routes through probeAndPersist which fans out all DefaultProbers including SavingsPlansProber. This PR closes the documentation and test coverage gap.

Test plan

• go test github.com/LeanerCloud/CUDly/internal/commitmentopts/... -- 83 pass (79 pre-existing + 4 new)
• go vet ./internal/commitmentopts/... -- clean

Summary by CodeRabbit

• Bug Fixes

  • Enhanced error handling to properly handle wrapped errors during validation, improving system resilience.

• Tests

  • Expanded test coverage for savings plans validation behavior and edge cases.