result: clean up test-to-requirement traceability

Apply the test-to-requirement traceability clean-up described in #522 to the Result component (`score/result/`).

Review every C++ gtest against the current `comp_req__result__...` needs. Add mandated `FullyVerifies` or `PartiallyVerifies` links, `TestType`, `DerivationTechnique`, and self-contained `Description` metadata where a test genuinely verifies a requirement. Reconcile requirement text and test behavior in both directions, and leave non-functional requirements that are verifiable only by inspection without artificial test coverage.

Start with issue #522 and inspect the C++ gtests under score/result/ alongside the current comp_req__result__... requirements. Map each genuine verification to the required metadata, reconcile requirement text with test behavior in both directions, and leave inspection-only requirements without artificial tests. Done means the Result traceability metadata is complete and consistent.

Written by the indexing model from the issue text.