docs(milestone): complete v1.15 — Nova Rebrand (tag v1.15.4)

P5 final-review-ship complete: dual-read fallback removed (REQ-164) —
core/env.py NOVA-only, .env.secrets load paths NOVA-only (G-106 retired),
nova_tagging.py hard-fails any acdl:* tag, legacy ACDL_* Gitea secrets
deleted, ACDL_LIFECYCLE_MODE/ACDL_LOCAL_TIER/ACDL_HITL_* exports removed
from scripts, SNS subject → Nova SoD halt (P1-2), bootstrap scripts
NOVA-only. Review: 2 P0 auto-fixed (duplicate delenv), P1-1/P1-2 resolved,
doc-drift fixed. Audit: tags v1.15.0-4 exist; traceability REQ-155..164
all complete; ARCHITECTURE naming table matches codebase. 615 pytest PASS;
run_ci.sh 3-stage PASS. NOVA_MIGRATION.md marked COMPLETE.

---ci---
project: acdl
phase: 5
milestone: v1.15
status: complete
phase_role: final
requirements:
  covered: [REQ-155, REQ-156, REQ-157, REQ-158, REQ-159, REQ-160, REQ-161, REQ-162, REQ-163, REQ-164]
  partial: []
---/ci---

scripts/run_lifecycle_test.sh

@@ -27,7 +27,7 @@ CI_VPC_OUTPUTS="${3:-}"
 
 # Lifecycle mode: "plan" (default, fast) or "full" (real apply against AWS).
 # Dual-read: NOVA_* preferred, ACDL_* fallback (removed in P5).
-LIFECYCLE_MODE="${NOVA_LIFECYCLE_MODE:-${ACDL_LIFECYCLE_MODE:-plan}}"
+LIFECYCLE_MODE="${NOVA_LIFECYCLE_MODE:-plan}"
 
 CONTRACT="modules/l1/${MODULE}/examples/${EXAMPLE}.yml"