feat(psychometric): recover 2017-era active asymptotes=TRUE TIPREDEFFECT rewrite on main

[seonghobae]

Summary

psychometric_core recovers the 2017-era active asymptotes=TRUE TIPREDEFFECT rewrite as the scalar −a · B on current main.

This is an independent successor of on-main asymTIPREDEFFECT -B z / a and on-main discreteTIPREDEFFECT. It does not depend on unpublished crates and is not stacked on queued #318–#349. cran/ctsem 2.5.0 summary.ctsemFit.R forms if(asymptotes==TRUE) TIPREDEFFECT <- -DRIFT %*% mxobj$TIPREDEFFECT$values when n.TIpred > 0. That rewrite is active and is in the outlist. Driver, Oud, and Voelkle (2017, Table 2, p. 12; Eq. 1, p. 4; Eq. 3, p. 5; §7.2, pp. 20–21; p. 16; JSS PDF re-opened 2026-08-31T05:20Z from https://www.jstatsoft.org/index.php/jss/article/download/v077i05/1104) name B TIPREDEFFECT. Form a first, then negate, then multiply by B. The rewrite is the coefficient B, not B z. When asymptotes=TRUE the stored TIPREDEFFECT is the asymptotic parameterization §7.2 names asymTIPREDEFFECT -B / a; multiplying by -DRIFT converts that stored value back to original B. The companion active rewrite CINT <- -DRIFT %*% CINT uses the same operator on a different matrix and is not this coefficient map.

A zero coefficient is exactly zero even if a ≥ 0. a ≥ 0 with a nonzero coefficient fails closed. Numeric: a = −0.5, B = 0.4 recovers 0.2, distinct from unstandardised TIPREDEFFECT (0.4), from unit asymTIPREDEFFECT -B / a (0.8), from discreteTIPREDEFFECT at Δt = 1 (≈ 0.3148), and from Table 2 CINT when κ = B. Stored -B / a = 0.8 recovers original TIPREDEFFECT 0.4. Unstandardised TIPREDEFFECT is not this rewrite. A non-event clock fails closed.

Meredith (1993) remains unread (Unpaywall 2026-08-31T05:10Z: is_oa: false; Springer content/pdf is an HTML stub; escholarship hits are citations). Mislevy (1991, Psychometrika, 56, 177–196, DOI 10.1007/bf02294457) remains unread on the same terms. Still not a Kalman filter, not a matrix expm, not ESEM estimation, not DSEM, and not ctsem estimation.

Verification

• cargo fmt --all
• cargo clippy -p psychometric_core --all-targets -- -D warnings
• cargo test -p psychometric_core --lib (189)
• cargo test -p psychometric_core --test multilevel_event_time_recovery_contract (108)
• cargo test -p psychometric_core --test scientific_claim_boundary_contract (53)
• RUSTDOCFLAGS='-D warnings' cargo doc -p psychometric_core --no-deps

Do not merge without independent non-author APPROVE + exact-head required-check success. Do not convert from draft. Do not self-approve.

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[seonghobae]

Queue-consolidation classification for the current recovery cycle: fold_into_landing_vehicle candidate — Longitudinal Psychometrics.

This PR overlaps #355 in the Driver/ctsem -a * B rewrite, but it is not safe to close either branch as a duplicate from title/equation similarity alone. Preserve this head's unique public naming, refusal guards, tests, doctoring, and documentation before folding into one current-main longitudinal landing vehicle. The eventual authority must compare both exact remote heads and retain the stronger published-example/recovery evidence without carrying unrelated architecture-row churn.

A separate crate or ADR number is not, by itself, a bounded-context boundary. The product boundary is the coherent Longitudinal Psychometrics model/recovery contract.