feat: the IC becomes the second metric vocabulary; rosters single-sourced

The A1 cut of #147 item 2, part 2 of 2 (the consumers), completing what
part 1 (the MetricVocabulary substrate) set up:

- aura-campaign's RANKABLE_METRICS hand-copy becomes a re-export of the
  backtest vocabulary's roster; the #190 guard test extends to pin the
  roster nesting (rankable == vocabulary roster, rankable within
  per-member, per-member within the research vocabulary) and the legacy
  exposure_sign_flips alias, so any drift fails a test loudly. The
  research and per-member rosters themselves stay hand-copies by ratified
  isolation (#190 accepted residual) — now oracle-pinned instead of trusted.
- aura-cli gains IcMetrics + IcKey implementing MetricVocabulary: the
  second PRODUCTION implementor. The standalone `aura measure ic`
  reduction now computes its permutation p via the shared null_draw +
  one_sided_p_laplace building blocks (independent draws instead of
  chained shuffles — statistically equivalent, deterministic per seed;
  emitted p values may differ in the last digits from #290's).
- Acceptance proven at the registry boundary: an engineered
  SweepFamily<IcMetrics> deflates through optimize_deflated to a LOW
  overfit probability and a noise family to a HIGH one (the permutation
  null, dispatched by the vocabulary — the deflation machinery is no
  longer baked-in R-only); same seed reproduces the identical
  FamilySelection; cross-vocabulary names are refused with the family's
  own roster in the prose (the C10 guard). A new cli_run E2E exercises
  the legacy alias through the real `aura runs family … rank` boundary.

Deviation from the plan, forced by the compiler: IcMetrics additionally
derives Debug (unwrap_err on the deflation Result needs it; mirrors
RunMetrics).

Verification: full workspace suite green (no FAILED, no compile errors),
clippy -D warnings clean, C18 goldens (cli_run, measure_ic, c28_layering)
green unchanged. A2 — measurement runs as sweep-family citizens — stays
deliberately deferred until a concrete campaign demand exists.

closes #147

crates/aura-backtest/src/metrics.rs

@@ -509,9 +509,9 @@ pub const R_BASED_METRICS: &[&str] =
     &["sqn", "sqn_normalized", "expectancy_r", "net_expectancy_r"];
 
 /// The rankable roster, in refusal-prose order — the roster this vocabulary
-/// resolves against (#147). The registry's own refusal prose and
-/// aura-campaign's re-export still hand-copy this list (not yet single-
-/// sourced from here); wiring them to read from here is deferred follow-up.
+/// resolves against (#147). The registry's refusal prose and
+/// `aura_campaign::RANKABLE_METRICS` (a re-export) both derive from this
+/// single source; neither hand-copies it anymore.
 pub const RANKABLE_METRICS: &[&str] = &[
     "total_pips",
     "max_drawdown",

crates/aura-campaign/src/lib.rs

@@ -144,14 +144,10 @@ pub const PER_MEMBER_METRICS: &[&str] = &[
     "sqn", "net_expectancy_r",
 ];
 
-/// The registry's rankable roster (`resolve_metric`'s name set) — the metrics
-/// a sweep/walk_forward stage may select on. Hand-copied (#190); drift fails
-/// safe (a name the registry would refuse is refused here first, before any
-/// member runs).
-pub const RANKABLE_METRICS: &[&str] = &[
-    "total_pips", "max_drawdown", "bias_sign_flips",
-    "sqn", "sqn_normalized", "expectancy_r", "net_expectancy_r",
-];
+/// The rankable subset a stage's `rank_by`/`select` may name — re-exported
+/// from the backtest vocabulary (single source, #147): this roster and the
+/// registry's refusal prose can no longer drift.
+pub use aura_backtest::RANKABLE_METRICS;
 
 /// Deflation resample count — re-exported from `aura-registry`'s shared
 /// definition (single-sourced, #199).

crates/aura-campaign/tests/metric_vocabulary_e2e.rs

@@ -107,3 +107,31 @@ fn metric_vocabulary_covers_all_shipped_scalar_metrics() {
          top-level enumeration)"
     );
 }
+
+/// #147: the rankable roster is single-sourced from the vocabulary impl, the
+/// rosters nest (rankable ⊆ per-member ⊆ research vocabulary), and the legacy
+/// CLI alias keeps resolving. Any drift fails here, loudly.
+#[test]
+fn rankable_roster_is_single_sourced_and_nested() {
+    use aura_engine::MetricVocabulary;
+
+    assert_eq!(
+        aura_campaign::RANKABLE_METRICS,
+        <RunMetrics as MetricVocabulary>::known(),
+        "campaign roster must BE the vocabulary's roster"
+    );
+    for name in aura_campaign::RANKABLE_METRICS {
+        assert!(
+            aura_campaign::PER_MEMBER_METRICS.contains(name),
+            "rankable metric '{name}' missing from PER_MEMBER_METRICS"
+        );
+    }
+    for name in aura_campaign::PER_MEMBER_METRICS {
+        assert!(
+            aura_research::metric_vocabulary().contains(name),
+            "per-member metric '{name}' missing from the research vocabulary"
+        );
+    }
+    // the pre-rename CLI alias must keep resolving (back-compat).
+    assert!(<RunMetrics as MetricVocabulary>::resolve("exposure_sign_flips").is_some());
+}

crates/aura-cli/src/main.rs

@@ -35,7 +35,7 @@ use aura_backtest::{
     RunMetrics, RunReport, SimBroker, SweepFamily, SweepPoint, WalkForwardResult, WindowRun,
     PM_FIELD_NAMES, PM_RECORD_KINDS,
 };
-use aura_analysis::{pearson_corr, permute, SplitMix64};
+use aura_analysis::{one_sided_p_laplace, pearson_corr, permute, MetricVocabulary, SplitMix64};
 use aura_std::{
     GatedRecorder, LinComb, Recorder, RollingMax, RollingMin, SeriesReducer, Sub,
 };
@@ -1844,6 +1844,51 @@ fn measurement_manifest(
     }
 }
 
+/// The IC measurement payload: the scalar plus its in-memory null inputs
+/// (the aligned pairs ride #[serde(skip)], mirroring RMetrics.net_trade_rs).
+/// The second production implementor of `MetricVocabulary` (#147) — the
+/// registry's deflation machinery dispatches to ITS permutation null.
+#[derive(Clone, Debug, serde::Serialize, serde::Deserialize)]
+struct IcMetrics {
+    information_coefficient: f64,
+    #[serde(skip)]
+    sigs: Vec<f64>,
+    #[serde(skip)]
+    frs: Vec<f64>,
+}
+
+/// The IC vocabulary's single resolved key.
+#[derive(Clone, Copy)]
+struct IcKey;
+
+impl MetricVocabulary for IcMetrics {
+    type Key = IcKey;
+
+    fn resolve(name: &str) -> Option<IcKey> {
+        (name == "information_coefficient").then_some(IcKey)
+    }
+    fn known() -> &'static [&'static str] {
+        &["information_coefficient"]
+    }
+    fn higher_is_better(_: IcKey) -> bool {
+        true
+    }
+    fn value(&self, _: IcKey) -> f64 {
+        self.information_coefficient
+    }
+    fn has_resampling_null(_: IcKey) -> bool {
+        true
+    }
+    fn null_draw(&self, _: IcKey, _block_len: usize, rng: &mut SplitMix64) -> Option<f64> {
+        if self.sigs.len() < 2 {
+            return None; // consumes no rng
+        }
+        let mut perm = self.sigs.clone(); // independent draw, not a chained shuffle
+        permute(&mut perm, rng);
+        Some(pearson_corr(&perm, &self.frs))
+    }
+}
+
 /// The pure IC reduction result (no CLI context) — unit-testable in isolation.
 /// Exercised by the in-crate `ic_tests` module and consumed by the run/command-path
 /// wiring in `dispatch_measure_ic`, which constructs `IcReport` from a live
@@ -1879,8 +1924,9 @@ impl IcReport {
 /// price ts-spine (a post-run array shift over recorded data — C2 governs in-graph
 /// nodes, not a completed run's trace); signal is aligned to it by EXACT timestamp
 /// match (unmatched dropped). `< 2` aligned pairs or zero variance → the degenerate
-/// floor `(0.0, 1.0)`. One-sided null (higher-is-better), Laplace-smoothed like the
-/// R deflation arm.
+/// floor `(0.0, 1.0)`. One-sided permutation null via the shared
+/// `MetricVocabulary::null_draw` + `one_sided_p_laplace` building blocks (#147);
+/// draws are independent permutations, deterministic given `seed`.
 fn information_coefficient(
     signal: &[(Timestamp, f64)],
     price: &[(Timestamp, f64)],
@@ -1912,17 +1958,18 @@ fn information_coefficient(
         return IcOutcome { information_coefficient: 0.0, overfit_probability: 1.0, n_pairs };
     }
     let raw = pearson_corr(&sigs, &frs);
-    // permutation null: shuffle signal against fixed returns, one-sided count
+    let member = IcMetrics { information_coefficient: raw, sigs, frs };
     let mut rng = SplitMix64::new(seed);
-    let mut perm = sigs.clone();
     let mut ge = 0usize;
     for _ in 0..permutations {
-        permute(&mut perm, &mut rng);
-        if pearson_corr(&perm, &frs) >= raw {
+        let draw = member
+            .null_draw(IcKey, 0, &mut rng)
+            .expect("n_pairs >= 2 checked above");
+        if draw >= raw {
             ge += 1;
         }
     }
-    let overfit_probability = (ge + 1) as f64 / (permutations as f64 + 1.0);
+    let overfit_probability = one_sided_p_laplace(ge, permutations);
     IcOutcome { information_coefficient: raw, overfit_probability, n_pairs }
 }
 
@@ -6790,4 +6837,97 @@ mod ic_tests {
         assert_eq!(out.n_pairs, 4, "only the 4 overlapping ts pair; price ts 0/3/6 and the decoys drop");
         assert!(out.information_coefficient > 0.99, "ic = {}", out.information_coefficient);
     }
+
+    fn ic_report(sigs: Vec<f64>, frs: Vec<f64>) -> aura_engine::RunReport<IcMetrics> {
+        aura_engine::RunReport {
+            manifest: aura_engine::RunManifest {
+                commit: "c".to_string(),
+                params: vec![("p".to_string(), aura_core::Scalar::f64(1.0))],
+                defaults: vec![],
+                window: (aura_core::Timestamp(1), aura_core::Timestamp(2)),
+                seed: 0,
+                broker: "b".to_string(),
+                selection: None,
+                instrument: None,
+                topology_hash: None,
+                project: None,
+            },
+            metrics: IcMetrics {
+                information_coefficient: aura_analysis::pearson_corr(&sigs, &frs),
+                sigs,
+                frs,
+            },
+        }
+    }
+
+    fn ic_family(members: Vec<aura_engine::RunReport<IcMetrics>>) -> aura_engine::SweepFamily<IcMetrics> {
+        aura_engine::SweepFamily {
+            space: vec![],
+            points: members
+                .into_iter()
+                .enumerate()
+                .map(|(i, report)| aura_engine::SweepPoint {
+                    params: vec![aura_core::Cell::from_f64(i as f64)],
+                    report,
+                })
+                .collect(),
+        }
+    }
+
+    /// #147 acceptance: the registry's deflation dispatches to the IC
+    /// vocabulary's OWN permutation null — a genuinely predictive family
+    /// deflates to a low overfit probability, a noise family to a high one.
+    #[test]
+    fn ic_family_deflation_dispatches_the_permutation_null() {
+        let ramp: Vec<f64> = (0..24).map(|i| i as f64).collect();
+        let engineered = ic_family(vec![
+            ic_report(ramp.clone(), ramp.clone()), // corr = 1.0: a real edge
+            ic_report(ramp.clone(), ramp.iter().rev().cloned().collect()), // corr = -1.0
+        ]);
+        let (winner, sel) =
+            aura_registry::optimize_deflated(&engineered, "information_coefficient", 500, 5, 0)
+                .expect("ic family deflates");
+        assert!((winner.report.metrics.information_coefficient - 1.0).abs() < 1e-12);
+        let p = sel.overfit_probability.expect("resampling-null arm sets a probability");
+        assert!(p < 0.05, "perfectly predictive family must not look like overfit: p={p}");
+
+        // orthogonal signal — IC exactly 0.0; permuted draws beat it ~half the time.
+        let noise = ic_family(vec![ic_report(
+            vec![0.03, 0.01, 0.04, 0.02, 0.05, 0.00, 0.06, -0.01],
+            vec![0.01, 0.02, 0.03, 0.04, -0.04, -0.03, -0.02, -0.01],
+        )]);
+        let (_, sel) =
+            aura_registry::optimize_deflated(&noise, "information_coefficient", 500, 5, 0)
+                .expect("noise family deflates");
+        let p = sel.overfit_probability.expect("probability present");
+        assert!(p > 0.1, "a noise family must carry a high overfit probability: p={p}");
+    }
+
+    /// Same seed → identical selection provenance (C1 through the generic path).
+    #[test]
+    fn ic_family_deflation_is_deterministic_given_seed() {
+        let ramp: Vec<f64> = (0..16).map(|i| i as f64).collect();
+        let fam = ic_family(vec![ic_report(ramp.clone(), ramp)]);
+        let a = aura_registry::optimize_deflated(&fam, "information_coefficient", 300, 5, 7)
+            .expect("deflate a");
+        let b = aura_registry::optimize_deflated(&fam, "information_coefficient", 300, 5, 7)
+            .expect("deflate b");
+        assert_eq!(a.1, b.1, "same seed must yield identical FamilySelection");
+    }
+
+    /// C10 guard: cross-vocabulary names are refused, and the refusal names
+    /// the family's REAL vocabulary.
+    #[test]
+    fn cross_vocabulary_names_are_refused_both_ways() {
+        let ramp: Vec<f64> = (0..8).map(|i| i as f64).collect();
+        let fam = ic_family(vec![ic_report(ramp.clone(), ramp)]);
+        let err = aura_registry::optimize_deflated(&fam, "sqn", 100, 5, 0).unwrap_err();
+        let prose = err.to_string();
+        assert!(
+            prose.contains("unknown metric 'sqn'") && prose.contains("information_coefficient"),
+            "refusal must name the IC vocabulary: {prose}"
+        );
+        // and the R side still refuses the IC name with ITS roster:
+        assert!(aura_registry::check_r_metric("information_coefficient").is_err());
+    }
 }

crates/aura-cli/tests/cli_run.rs

@@ -1146,6 +1146,70 @@ fn runs_families_list_and_per_family_rank_across_invocations() {
     let _ = std::fs::remove_dir_all(&cwd);
 }
 
+/// #147: the pre-rename metric name `exposure_sign_flips` still resolves
+/// through the real, user-facing `aura runs family <id> rank <metric>` path —
+/// not just through a direct `MetricVocabulary::resolve` call in a unit test.
+/// Task 4 re-exports `aura_campaign::RANKABLE_METRICS` from the single-sourced
+/// backtest vocabulary instead of hand-copying it; were the vocabulary's
+/// `resolve()` match arm for the legacy alias ever dropped in that refactor,
+/// this is the only test that would catch it at the CLI's actual observable
+/// boundary (exit code + stdout), rather than inside the crate that owns the
+/// vocabulary.
+#[test]
+fn runs_family_rank_accepts_legacy_exposure_sign_flips_alias() {
+    let cwd = temp_cwd("runs-rank-legacy-alias");
+    let fixture = format!("{}/examples/r_sma.json", env!("CARGO_MANIFEST_DIR"));
+    let sweep = Command::new(BIN)
+        .args([
+            "sweep", &fixture,
+            "--axis", "sma_signal.fast.length=2,4",
+            "--axis", "sma_signal.slow.length=8,16",
+        ])
+        .current_dir(&cwd)
+        .output()
+        .expect("spawn sweep");
+    assert!(sweep.status.success(), "sweep stderr: {}", String::from_utf8_lossy(&sweep.stderr));
+
+    let rank = Command::new(BIN)
+        .args(["runs", "family", "sweep-0", "rank", "exposure_sign_flips"])
+        .current_dir(&cwd)
+        .output()
+        .expect("spawn rank");
+    assert!(
+        rank.status.success(),
+        "the legacy alias must still resolve, not usage-error: stderr={}",
+        String::from_utf8_lossy(&rank.stderr)
+    );
+    let rank_out = String::from_utf8(rank.stdout).expect("utf-8");
+    assert_eq!(rank_out.lines().count(), 4, "all 4 members rank: {rank_out:?}");
+    // the renamed field is what actually ships in the JSON — the alias is a
+    // resolve()-only back door, never a second output key.
+    assert!(
+        rank_out.lines().all(|l| l.contains("\"bias_sign_flips\":")),
+        "output still serializes under the new key: {rank_out:?}"
+    );
+    assert!(
+        !rank_out.contains("\"exposure_sign_flips\":"),
+        "the legacy key must never appear in output: {rank_out:?}"
+    );
+
+    let flips: Vec<i64> = rank_out
+        .lines()
+        .map(|l| {
+            let key = "\"bias_sign_flips\":";
+            let start = l.find(key).expect("line has bias_sign_flips") + key.len();
+            let tail = &l[start..];
+            let end = tail.find([',', '}']).expect("token end");
+            tail[..end].parse().expect("bias_sign_flips is an integer")
+        })
+        .collect();
+    // bias_sign_flips is a lower-is-better metric (fewer direction reversals),
+    // so `rank` orders ascending here — unlike total_pips's descending order.
+    assert!(flips.windows(2).all(|w| w[0] <= w[1]), "rank not ascending by the aliased metric: {flips:?}");
+
+    let _ = std::fs::remove_dir_all(&cwd);
+}
+
 #[test]
 fn runs_list_and_rank_are_retired_and_exit_two() {
     // `aura runs list` / `runs rank <metric>` were retired (#73): families