Model Train G-b/C-cal: gate simulation + calibration report (docs only)

REPORT-FIRST per the arc order. G-a is HELD — the data changes the
recommended dials. No engine code touched.

Replayed against live ledger_entries (576 rows, 6 game days, 470 settled)
because the "30 days of stored snapshots" does not exist: snapshot Redis
keys are latest/previous only at 24h TTL, and no backtest harness exists
anywhere in the repo.

Findings that change the plan:
- The -400 floor shipped this morning was the whole win: past -400 hit
  80.3% against an 86.9% breakeven = -13.29u / -7.7% ROI on 173 settled.
- Arc 2's incremental cut over the live gate is ~11 props in 6 days. The
  only material change is gating the flex band behind 2x EV.
- The flex band (-161..-250) is our BEST band (+2.2% ROI, n=70) and the
  takeable band is flat (-0.3%, n=209) — the opposite of the assumption
  behind EDGE_FLEX_WALL. Recommend shipping the knob with enforcement
  OFF until EV is persisted and measured.
- ev_pct/p_win are on NO ledger row, so the EV half of the gate cannot be
  replayed at all. C-led (persist EV) is now the highest-leverage item.
- Confidence is monotonic but understates hit rate by ~20-25 points, and
  the entire public ledger contains only B and C grades — zero A/A+.
  That breaks hero v2 (isAB) and undermines "A-RATED" copy. Escalated.
- L-a answered: alt_lines carry NO odds and the feed has no alternate
  markets. L-b is blocked on a data source, not engine work.
- C-led needs no odds backfill (locked_odds 99.1% populated).
- U-deg: the projection==0 leak is already closed (0 since 07-18).
- C4 confirmed in data (359/376 MLB closes == the lock). Stays suppressed.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01SmNjJAwEnqHPtXbvSZR8kA

specs/model-train.md

@@ -153,6 +153,34 @@ timestamp) is unchanged. `toHero` now also passes through
 
 ---
 
+## 2A. ARC 2+ BOARD — STATUS (Kev's arc list, 2026-07-19)
+
+Full arc definitions live in the Session-63 order. Status only here; update as each ships.
+
+| Item | Status | Note |
+|---|---|---|
+| **G-a** the real gate | **HELD for ruling** | Built nothing yet — the G-b report changes the recommended dials. See `specs/audit-data/gate-simulation.md` §2.4. |
+| **G-b** gate simulation | ✅ **REPORTED** | `specs/audit-data/gate-simulation.md`. Replayed over the ledger, NOT snapshots (no 30d snapshot store exists). |
+| **G-c** never-empty honesty | open | Rare but real on thin MLB nights. |
+| **S-a** line-moved truth | open | Shares plumbing with C-clv — build together. |
+| **S-b** board ranks on EV | open | Blocked-ish: EV not persisted; live payload has it. |
+| **L-a** per-rung odds? | ✅ **REPORTED — NO** | Rungs are synthetic, carry no price. Feed offers no alternate markets. §3 of the report. |
+| **L-b** per-rung EV ladder | **BLOCKED** | Needs a real price per rung. Probe PropLine first. |
+| **C-cal** calibration | ✅ **REPORTED** | Confidence monotonic but ~20-25pts miscalibrated; **only B/C grades ever emitted**. |
+| **C-led** ledger speaks value | open — **recommended next** | `locked_odds` already 99.1% populated: units/ROI need no backfill. EV columns are net-new, forward-only. |
+| **C-clv** fix C4 | open | Confirmed broken in data (359/376 MLB closes == lock). Keep suppressed. |
+| **D-ref** visible refusals | partial | Copy already ships on refusals; new `gate_*` reasons land with G-a. |
+| **D-par** parlay lab | open | Gate must NOT apply inside the Lab. |
+| **D-tier** tier gating | **DECIDED, not enforced** | Free/Analyst: value marker + grade + triplet. Desk: ladder + per-rung EV + Kelly. Today ladder/Kelly are already Desk-gated; triplet ungated = correct per this ruling. |
+| **D-ev** consolidate EV | open | `devig.evPct` vs `processing/EVCalculator.js` (used only by `UnifiedOddsProvider`). |
+| **U-deg** MLB degradation | ✅ **STATUS REPORTED** | `projection==0` leak **already closed** (0 occurrences since 07-18). `edge_pct` scale still broken. |
+| **U-fp** Arc 1 fingerprint | open | Do it on the first deploy this train ships. |
+
+### Backtest harness
+**None exists** (grep-verified). `migrations/006` defines `grade_outcomes` +
+`player_calibrated_weights` and **no code reads or writes them**. The G-b/C-cal replay was
+done in SQL against `ledger_entries`; a real harness is still owed before any weight change.
+
 ## 3. NOT YET BUILT — checklist to reconcile against the full arc list
 
 Verified absent from the codebase as of `7a925f4`. Kev supplies the complete arc list;