feat(cli): generalize applicability tag + honest R-expectancy refusal prose (fieldtest 0108 F8)

--metrics now tags the four generalizable names (expectancy_r,
net_expectancy_r, sqn, sqn_normalized) via check_r_metric as the
predicate — the registry's own R-expectancy rule, no fourth roster
site (#190). The GeneralizeNonRMetric refusal names the real rule
with the roster pointer instead of mislabeling R-denominated-but-
unranked metrics (max_r_drawdown is a drawdown in R, not a 'pip
metric').

RED-first (tdd-author handoff): the extended --metrics pins and the
flipped prose pins (unit + seam) observed failing on the old output.

Gates: workspace 1026/0, clippy -D warnings clean.

closes #207

crates/aura-cli/src/campaign_run.rs

@@ -68,8 +68,9 @@ pub(crate) fn exec_fault_prose(f: &ExecFault) -> String {
             "campaign has {available} instrument(s); std::generalize needs at least 2"
         ),
         ExecFault::GeneralizeNonRMetric { metric } => format!(
-            "std::generalize metric \"{metric}\" is not an R metric (gross/net R \
-             families generalize; pip metrics do not)"
+            "std::generalize metric \"{metric}\" is not in the rankable R-expectancy \
+             family (expectancy_r, net_expectancy_r, sqn, sqn_normalized generalize; \
+             see: aura process introspect --metrics)"
         ),
         ExecFault::ZeroBootstrapParam { stage, field } => format!(
             "process stage {stage}: monte_carlo {field} must be > 0"
@@ -500,16 +501,21 @@ mod tests {
     }
 
     #[test]
-    /// generalize's R-metric refusal names the metric and the R-only
-    /// rationale (pip metrics are not comparable across instruments).
+    /// #207 (fieldtest 0108 F8): generalize's refusal names the REAL rule — the
+    /// rankable R-expectancy family that generalizes — and points at the roster
+    /// verb, instead of the old "pip metrics do not" mislabel (which was wrong
+    /// for R-denominated-but-unranked names like max_r_drawdown). The four
+    /// accepted names are enumerated in the prose as a fail-safe hint; the
+    /// durable source is the `(see: …)` roster pointer.
     fn generalize_non_r_metric_prose_names_the_metric() {
         let prose = exec_fault_prose(&ExecFault::GeneralizeNonRMetric {
             metric: "total_pips".into(),
         });
         assert_eq!(
             prose,
-            "std::generalize metric \"total_pips\" is not an R metric (gross/net R \
-             families generalize; pip metrics do not)"
+            "std::generalize metric \"total_pips\" is not in the rankable R-expectancy \
+             family (expectancy_r, net_expectancy_r, sqn, sqn_normalized generalize; \
+             see: aura process introspect --metrics)"
         );
         assert!(!prose.contains("GeneralizeNonRMetric"), "Debug leak: {prose}");
     }

crates/aura-cli/src/research_docs.rs

@@ -82,7 +82,10 @@ fn print_metric_roster() {
     for name in aura_research::metric_vocabulary() {
         let rankable = aura_campaign::RANKABLE_METRICS.contains(name);
         let gate = aura_campaign::PER_MEMBER_METRICS.contains(name);
-        let tag = match (rankable, gate) {
+        // The generalize applicability is the registry's own R-expectancy
+        // predicate — no fourth roster site (#190/#207).
+        let generalize = aura_registry::check_r_metric(name).is_ok();
+        let base = match (rankable, gate) {
             (true, true) => "rankable | gate",
             (false, true) => "gate",
             // Unreachable today (the rankable roster is a subset of the
@@ -90,7 +93,11 @@ fn print_metric_roster() {
             (true, false) => "rankable",
             (false, false) => "annotation",
         };
-        println!("{name:<24} {tag}");
+        if generalize {
+            println!("{name:<24} {base} | generalize");
+        } else {
+            println!("{name:<24} {base}");
+        }
     }
 }