Quantum Structural Theory of Harmony (QSTH 6.9) — I-Dim Elementary Coupling and Semi-I-Dim Classification of the Fine Structure Constant α ≈ 1/137

QSTH Publication 6.9 introduces an audit-first framework for cross-scale mapping (Planck ↔ cosmology) and a disciplined classification of the fine-structure constant α ≈ 1/137 as a semi-I-Dim candidate interface signature (CAND), while preserving its standard status as a running 4D coupling α(μ) in QED/QFT. The core contribution is methodological and verification-oriented: QSTH 6.9 separates what is CANON (pure scale definitions and non-controversial identities) from what is CAND (candidate bridges / interface signatures), and introduces a visible registry, evidence states (FILL / PARTIAL / EMPTY), and an explicit PASS / FAIL / INCONCLUSIVE gate. This prevents category errors (candidates mistaken for facts) and turns speculative bridges into a reproducible testing program. What is new / original in QSTH 6.9 semi-I-Dim classification: a strict middle category for standard couplings (like α) when used as candidate interface signatures—without claiming an origin or replacing α(μ). audit vocabulary + verification gate embedded directly in the publication (CANON/CAND + FILL/PARTIAL/EMPTY + PASS/FAIL/INCONCLUSIVE). CAND Registry (Table 1): a reader-friendly “visible firewall” listing candidates, what they assert / do not assert, and how they must be tested. A disciplined “Two transparencies” distinction: local interface transparency (field ↔ charge, 4D): parameterized by α global transparency (Planck vacuum ↔ cosmological vacuum): parameterized by α_I-Dim = ℓ_P / L_ΛThe work tests whether both transparencies can belong to one unified map—without claiming identity. Verification program (H1/H2) H1 (TP-αH1): cross-method α consistency using public metrology channels, including an explicit decision gate and a Round-1 closure verdict (INCONCLUSIVE pending full systematics/correlation audit). H2 (TP-αH2): Δα/α(z) redshift-coherence protocol with a pre-registered PASS/FAIL/INCONCLUSIVE gate, including: Round-1: single-target null-test quality check (ESPRESSO) Round-2: subsample robustness test (e.g., UVES SQUAD DR1) Files included in this record Core (EN, FINAL) — QSTH 6.9 main publication (semi-I-Dim, registry, gates, and test plan) Appendix A (EN, FINAL) — Method Note: renormalization safety, TP-α1…TP-α3, PASS/FAIL templates Appendix B (EN, FINAL) — Connections table: comparative view of couplings and cross-scale ratios Appendix C (EN, FINAL) — Context Map: navigational links to QSTH 6.0–6.8 (no topic expansion) Appendix D (EN, FINAL) — H1 public-data pilot checks, decision gate, Round-1 verdict Appendix E (EN, FINAL) — H2 redshift-coherence test: gate and protocol (public data) How to cite / how to read Start with the Core (definitions + audit gate + CAND registry). Use Appendix D/E as the operational verification layer (H1/H2). Appendices B/C provide orientation and cross-links; Appendix A provides the method templates and renormalization safety rules. QSTH 6.9 is built as an audit-first verification engine: CANON stays factual, CAND stays testable, and every bridge must pass an explicit PASS/FAIL/INCONCLUSIVE gate. The long-game criterion is not elegance but reproducible convergence of the same audit signature across independent channels, datasets, and (eventually) multiple I-Dim projections. Related QSTH Zenodo records (recommended entry points) • QSTH 1.0 — Foundational Publication (DOI: 10.5281/zenodo.17455814)• QSTH 1.0 — Horizon Set (DOI: 10.5281/zenodo.18015679)• QSTH 4.1 — Planckian Horizon 2.0: The Entropic bridge between Quantum and Cosmological Reality (DOI: 10.5281/zenodo.17899867)• QSTH 5.2 — OMEG: The Operational Metric Plane of Entropic Geometrodynamics (OMEG) (DOI: 10.5281/zenodo.17937840)• QSTH 6.0 — The Info-Dim (I-Dim) Package (DOI: 10.5281/zenodo.18156387)• QSTH 6.1 — Entropic Zero (E0) & Entropic Stars (DOI: 10.5281/zenodo.18165254)• QSTH 6.2 — Vacuum as an Entropic Ledger and the Origin of Baryon Asymmetry (DOI: 10.5281/zenodo.18641674)• QSTH 6.5 — Planckian Horizon 2.0 as a Ledger boundary (DOI: 10.5281/zenodo.18649631)• QSTH 6.6 — Planckian Horizon 2.0 as an Operational entropic-coherence principle (DOI: 10.5281/zenodo.18701036) • QSTH 6.7 — Variational Entropic Lagrangian (R10) (DOI: 10.5281/zenodo.18715255) . • QSTH 6.8 — Mendeleev Table of Relationships among Physical Constants (DOI: 10.5281/zenodo.18762028)