feat(drift_ledger): literal-100% residue — dichotomy wave

Port the last audit-missing fn name-preserving: _auto_fix_decision,
the facade routing probe's reunited-crate twin (delegates in-process to
the existing auto_fix_decision kernel; the loader-failure fallback arm
cannot fire in-process). Battery k_auto_fix replay now enters through
the twin — 8/8 green. Truth regen x2 byte-identical; embedded truth
== live regen; RUNE_DL_CORE=auto parity pass 87 cases byte-identical
against the built .so; clippy -D warnings clean; adjacent pytest
27/27 BOTH pins (RUNE_DL_CORE=python|auto). Fn coverage 20/21 -> 21/21.

src/rust/drift_ledger/src/branch_battery.rs

@@ -7,7 +7,7 @@
 //! are replayed byte-for-byte, the IO-seam groups ride along as provenance
 //! and are re-verified live by the generator's RUNE_DL_CORE=auto parity pass).
 
-use crate::{anchor_record, auto_fix_decision, check_alerts, diff_blocks,
+use crate::{_auto_fix_decision, anchor_record, check_alerts, diff_blocks,
             fix_decision, ledger_path_for, sha, snapshot_entry};
 
 const TRUTH: &str = r###"{
@@ -2111,9 +2111,9 @@ fn check_alerts_matches_oracle() {
 #[test]
 fn auto_fix_decision_matches_oracle() {
     for (idx, case) in truth()["k_auto_fix"].as_array().expect("k_auto_fix array").iter().enumerate() {
-        let got = auto_fix_decision(case["input"]["label"].as_str().unwrap_or(""),
-                                    matches!(case["input"]["anchored"], serde_json::Value::Bool(true)),
-                                    matches!(case["input"]["has_last_good"], serde_json::Value::Bool(true)));
+        let got = _auto_fix_decision(case["input"]["label"].as_str().unwrap_or(""),
+                                     matches!(case["input"]["anchored"], serde_json::Value::Bool(true)),
+                                     matches!(case["input"]["has_last_good"], serde_json::Value::Bool(true)));
         assert_eq!(got, case["expected"], "k_auto_fix case {}", idx);
     }
 }

src/rust/drift_ledger/src/lib.rs

@@ -155,6 +155,15 @@ pub fn auto_fix_decision(label: &str, anchored: bool, has_last_good: bool) -> Va
     }
 }
 
+/// Name-preserving twin of the facade's `_auto_fix_decision` routing probe:
+/// the oracle wrapper's whole body is delegate-to-dl_loader-else-Python —
+/// in the reunited crate the delegation is in-process (the loader-failure
+/// fallback arm can't fire), so the twin forwards to [`auto_fix_decision`].
+/// The k_auto_fix truth rows pin this entry point.
+pub fn _auto_fix_decision(label: &str, anchored: bool, has_last_good: bool) -> Value {
+    auto_fix_decision(label, anchored, has_last_good)
+}
+
 /// Python round(x, 3): correct rounding of the binary value with ties-to-even
 /// (the same contract Rust's {:.3} formatting implements).
 fn py_round3(x: f64) -> f64 {