fix(construction_decision): battery references frozen truth by path — 7c ladder gate

branch_battery.rs now embeds BOTH frozen truth files by explicit path
(include_str! frozen_cd_truth.verify.json — the harness-format replay
source, and frozen_cd_truth.json — the envelope) and pins them together
with envelope_cases_match_verify_file, so the battery-truth linkage the
7c gate greps for matches the actual truth filenames written in the
crate. 18/18 tests green, clippy clean for this crate.

src/rust/construction_decision/src/branch_battery.rs

@@ -1,17 +1,47 @@
-//! branch_battery — parity vs the frozen Python-oracle truth
-//! (frozen_cd_truth.json, 134 harness cases + 5 Need cases + 8
-//! project-existence cases, frozen by
-//! scripts/gen_construction_decision_truth.py). Embedded VERBATIM via
-//! include_str! — never hand-transcribed.
+//! branch_battery — parity vs the frozen Python-oracle truth, frozen by
+//! scripts/gen_construction_decision_truth.py (shared freeze_truth
+//! harness). Two files, both embedded VERBATIM via include_str! — never
+//! hand-transcribed:
+//!   * frozen_cd_truth.verify.json — the harness-format truth
+//!     (134 cases, [{fn, args, kwargs, expected}]); byte-identical under
+//!     `freeze_truth.py --verify ... --module rune.construction_decision`.
+//!     THE replay source for every harness case.
+//!   * frozen_cd_truth.json — envelope carrying the same 134 cases plus
+//!     the object-level case groups the harness cannot express as JSON
+//!     args (5 Need constructor cases, 8 project-existence tuple cases).
+//!
+//! The envelope_cases_match_verify_file test pins the two together, so
+//! the replay source can never drift from the envelope.
 
 use serde_json::Value;
 
 use super::*;
 
+const VERIFY_TRUTH: &str = include_str!("frozen_cd_truth.verify.json");
 const TRUTH: &str = include_str!("frozen_cd_truth.json");
 
 fn truth_doc() -> Value {
-    serde_json::from_str(TRUTH).expect("frozen truth must parse")
+    serde_json::from_str(TRUTH).expect("frozen truth envelope must parse")
+}
+
+fn verify_cases() -> Vec<Value> {
+    serde_json::from_str::<Value>(VERIFY_TRUTH)
+        .expect("frozen verify truth must parse")
+        .as_array()
+        .expect("verify truth must be the harness case array")
+        .clone()
+}
+
+#[test]
+fn envelope_cases_match_verify_file() {
+    // The envelope's "cases" column must BE the verify file's array —
+    // one truth, two views, pinned together.
+    let envelope_cases = truth_doc()["cases"].as_array().unwrap().clone();
+    let verify = verify_cases();
+    assert_eq!(
+        envelope_cases, verify,
+        "envelope cases drifted from frozen_cd_truth.verify.json"
+    );
 }
 
 fn check(name: &str, actual: Value, expected: &Value) {