Contract-First Causal Fusion for Superconducting Magic-State Cultivation: Recovery Instruments, Coherent Consumers, and Conditional Yield Frontiers

Rejected cultivation histories can retain resources usable by a declared future. Causal-Relational Closure (CRC) identifies equivalence by complete future response; Quantum Transfer Level (QTL) constructs and verifies outcome-resolved transitions. The design object shifts from microscopic fault identity to the probability-bearing future operation. A restricted recovery instrument transports to a four-body witness on existing ancillary connectivity. A coherent-consumer extension reduces an ideal closed logical injection channel exactly to two unnormalized weights and emits a constructed 56-controlled-Z parent with 51 controlled-Z gates. Under a specified stochastic model and shared heralded distance-three injection consumer with approximately 74% encoded-process overlap, a frozen 68-history policy predicts 20.6%–23.2% greater output rate at matched modeled quality after weighting early records by Google’s measured frequencies. Quality-margin frontiers identify 36- and 33-history policies that improve rate and pass matched modeled quality in both circuit bases, with and without prefix reweighting. Gains are 17.5%–20.1% unweighted and 15.7%–18.3% weighted. Source-noise sensitivity retains the frozen 68-history policy and apparatus. Validation against 600,000 original-circuit records exposes source-model miscalibration in helper histories and destructive logical contrasts, including the Z-basis zero-history cohort. This diagnostic does not quantify the discrepancy visible to the coherent consumer’s quotient. Exact instrument and emission results remain valid within their contracts; receiving-apparatus fault collisions withhold fault-tolerant promotion. Complete derivations, circuits, record tables, and bounded operator-effect calculations accompany the conditional model predictions; hardware recovery gains remain unmeasured