#51 overnight_gap_logret_sq

In plain terms

The squared log jump between this bar's open and the previous bar's close — the pure between-bar gap component of volatility that range-based estimators (Parkinson, Garman-Klass) throw away. Flags regimes where price jumps between bars rather than traveling within them.

What this iteration will do

1. worktree, branch feat/odb-ext/overnight_gap_logret_sq; draw/refresh the dashboard flowchart FIRST (R6)
2. freeze the gap-aware oracle oracle_overnight_gap_logret_sq.py over the frozen fixture → forex_orthogonal_extension_overnight_gap_logret_sq_oracle-v1.jsonl + .sha256 (transcribed from probe kernel k_overnight_gap_logret_sq — NEVER the discovery harness)
3. port the causal Rust kernel + rolling state (libm-only transcendentals, NaN/Inf-total, compute-then-update)
4. wire the producer in the SAME PR: BarOrthogonalExtV1 field · writer.rs BarRow/COLUMN_NAMES · schema.sql TEXT-only DDL · feature_metadata.yaml · v4 cohort slot (R4 no split-brain)
5. robustness suite ALL GREEN: non-vacuous parity (batch ≡ streaming) at the locked tolerance · ≥2-symbol replication · crash-stress · golden snapshot · hardening witnesses (RG)
6. mise run rust:check + mise run check:all-gates — red gate ⇒ fix-or-halt (R7), never --no-verify
7. Challenge-and-Held (1 Attacker + 1 Defender) → committed challenge-and-held-*.md; fix conceded gaps before PR-open
8. open the PR (never merge) · overwrite this page with full results · append the iteration-ledger row · Pushover briefing