audit: batch tidy — exhaustive bind-error prose + the carry unit note

Cycle-close audit over the /boss batch 84e1075..bdafbde (#258 #259
#264 #266 #247 #265 #269). Architect verdict: substance clean — C1
byte-identity (conduit serde-skipped, pinned floats verbatim, uncosted
bit-identical), C10 one-home-for-cost (all four conduit consumers read
the already-netted series), C18 (conduit off the wire, --version and
manifest single-sourced) all hold. Two medium debt items, both fixed
here rather than carried:

- render_bind_error's catch-all Debug-framed the remaining BindError
  variants, making #269's no-identifier-on-stderr claim argv-gated
  rather than structural. The match is now exhaustive: DuplicateBinding,
  EmptyAxis, EmptyRange render as axis-usage prose; a Compile fault — a
  blueprint defect, not a usage error — renders as a prose frame with
  the compile detail explicitly labelled internal (per-variant
  CompileError prose belongs to the graph-build surface, not this
  boundary). Unit tests pin the arms.
- The #265 knob-unit notes covered constant and vol_slippage but not
  carry.carry_per_cycle, which carries the identical price-unit-vs-R
  trap; the note set and its pins now cover all three cost components.

No regression scripts are configured (the architect is the sole gate);
full workspace suite green, clippy clean. Spec and plan working files
discarded per the audit lifecycle.

refs #265 refs #269

crates/aura-cli/tests/research_docs.rs

@@ -717,6 +717,15 @@ fn campaign_introspect_unwired_annotates_cost_and_risk_knob_units() {
         low.contains("scales the stop distance"),
         "vol.k must be annotated as SCALING the stop distance (the risk-unit lever): {out}"
     );
+
+    // carry.carry_per_cycle — the identical price-unit-vs-R trap, accruing per
+    // held cycle (audit follow-up to #265: the note set must cover ALL three
+    // cost components, not two of three).
+    assert!(low.contains("carry_per_cycle"), "the carry knob must still be named: {out}");
+    assert!(
+        low.contains("price units per held cycle"),
+        "carry_per_cycle must be annotated as a PRICE-unit per-held-cycle accrual: {out}"
+    );
 }
 
 #[test]