Higher‑Dimensional Blast + Leakage — Last‑Mile Meta‑Release (PTA→LISA), v2025‑09‑09

**What this is.** A *research compendium* (“last‑mile” kit) that freezes figures, numbers, scripts, and notes supporting a data‑driven test of a minimal higher‑dimensional **blast + leakage** picture using the stochastic gravitational‑wave background (SGWB). It bundles: (i) publication‑ready figures & caption tables; (ii) recomputed posterior metrics; (iii) small Python helpers to reproduce one‑number gates; (iv) a PRL‑style abstract, referee‑friendly checklists, and a one‑screen runbook.

**Key reproducible numbers (from D_posterior.csv):**  
Median \(D=4.8400\); 68% band \([4.7044,\,5.0016]\) (width 0.2972); 90% band \([4.6359,\,5.1083]\); \(\Pr(D>4)\simeq1.000\); posterior mass in \(D\in[4.6,5.05]\)=0.884. These quantify an *effective* dimensionality \(D=4+\gamma/\eta\) extracted from the PTA spectrum; 4‑D GR is recovered in the IR.

**What’s inside (selected):**
- Figures: `D_posterior_histogram_TODAY.png`, `Bayes_tiers_reference_TODAY.png`, `TIS_vs_alpha_illustrative_TODAY.png`.
- Tables/metrics: `Caption_fT_numbers_TODAY.csv`, `D_posterior_metrics_TODAY.txt`.
- Scripts (runnable one‑liners):  
  `pta_coherence_index.py` (PTA coherence index, PCI);  
  `compute_bayes_from_bic.py` (ΔBIC → Bayes tiers);  
  `triangle_intersection_score.py` (CMB parity “triangle” TIS);  
  `estimate_epsilon_leak.py` (integrated GW energy → \(\epsilon_{\rm leak}\)).
- Paperwork: `PRL_Abstract_2025-09-09.txt`, `TOE_Criteria_Assessment.md`, `Anomaly_Consistency_Checklist.md`, `GUT_Embedding_Note.md`, `Public_Explainer.md`, `README_LAST_MILE.md`.
- Repro environment & provenance: `environment.yml`, `CITATION.cff`, `RELATIONS.json`.

**How to reproduce (one screen):**
```bash
# Coherence across PTAs (needs three D-sample CSVs you provide)
python pta_coherence_index.py --files NG15_D.csv EPTA_D.csv PPTA_D.csv   # → PCI_report.txt

# Strings vs leakage (add 'strings' BIC row to the provided template first)
python compute_bayes_from_bic.py DeltaBIC_merged_vNEXT_WITH_STRINGS_TEMPLATE.csv  # → Bayes_Tiers_Summary.txt

# CMB parity leg (when α±σα is available)
python triangle_intersection_score.py --D-posterior D_posterior.csv \
  --alpha ALPHA_DEG --sigma SIGMA_DEG --susy-Dmin 4.6 --susy-Dmax 5.05       # → TIS_report.txt