Extends SealedPracticeTrace for externally bound candidate episodes per ADR-0233. Adds candidate_attempt_binding_ids to trace identity, bound trace input/seal entry points, and end-to-end bound episode tests without mutating GeometricSearchRun.candidate_attempts.
Adds immutable practice-trace input, sealed-trace, and trace-refusal records with deterministic identity-chain validation after the Contract/ Proof Replay Adapter, as authorized by ADR-0230.
