fix: reduce claim binding validation complexity

[Brad-Edwards]

Summary

Reduces the SonarCloud-reported complexity in validate_behavioral_claim_binding, the function actually associated with the open issue on #977.

Related issues

• Addresses the remaining SonarCloud quality-gate finding on Dev #977.

Changes

• Extract taxonomy and relation resolution into a focused helper.
• Validate required relation bindings through a compact requirement table.
• Preserve all existing validation errors and return behavior.

Test plan

• 103 behavioral-relation, opacity, and repeatability tests pass
• Repository lint passes
• Repository policy check passes
• Module complexity audit reports a maximum of 9 and the flagged function at 2

Checklist

• Code follows project coding standards
• No semantic behavior change
• No published contract schema changes
• PR title is a Conventional Commit
• No architectural documentation update needed

Notes for review

The prior fix refactored a different function because the Sonar line number was interpreted against the wrong source revision. This change follows the stable Sonar issue key to the actual function and audits the complete module against the same complexity threshold.