Computes a net-benefit screen for a direct-indexing program from caller-declared synthetic inputs: net benefit in basis points is the declared expected tax alpha minus the declared fee delta (direct-indexing fee minus ETF expense ratio), rounded half-up to 2 decimal places with the arithmetic restated in a trace. The verdict reports the sign of that declared arithmetic only: FIT_POSITIVE, FIT_NEGATIVE, or FIT_NEUTRAL. When the caller also declares a holding period and an alpha-exhaustion horizon, an exhaustion warning is added; when the caller declares a concentrated stock position, an unwind note is added. HARD FENCE: this is a deterministic calculator over declared numbers under named rules; it is never advice, never an optimizer, and it prices no cost it has not been given.
compute_proof_ready: deferred. No formal correctness proof has been produced for this kernel; the result above is a deterministic recompute, verified by a property-test floor, not a proven one.