verify(P3): dead-code-and-stale-prefix-cleanup — 4-layer verify PASS + ship

VERIFY: structural — dead export + stale comments + prefixes gone; behavioral — 616 tests + CI PASS; quality — env-override test updated.

---ci---
project: acdl
phase: 3
milestone: v1.16
status: complete
phase_role: execution
requirements:
  covered: [REQ-167]
  partial: []
---/ci---

scripts/run_l2_lifecycle_destroy.sh

@@ -14,8 +14,8 @@
 # parity with the L1 matrix, but $2 is accepted-but-ignored here (documented,
 # not a bug).
 #
-# Lifecycle mode (REQ-134): NOVA_LIFECYCLE_MODE (dual-read NOVA_* preferred,
-# ACDL_* fallback until P5) default "plan" = no-op
+# Lifecycle mode (REQ-134): NOVA_LIFECYCLE_MODE (NOVA_* only; ACDL_*
+# fallback removed in v1.15 P5) default "plan" = no-op
 # (plan mode never applies resources, so there is nothing to destroy).
 # Set to "full" for the real `--destroy` against live AWS.
 set -euo pipefail
@@ -25,7 +25,7 @@ cd "$ROOT"
 MODULE="$1"
 
 # Lifecycle mode: "plan" (default) skips destroy; "full" runs the real destroy.
-# Dual-read: NOVA_* preferred, ACDL_* fallback (removed in P5).
+# NOVA_* env vars only (ACDL_* fallback removed in v1.15 P5, REQ-164).
 LIFECYCLE_MODE="${NOVA_LIFECYCLE_MODE:-plan}"
 
 if [ "$LIFECYCLE_MODE" != "full" ]; then