diff --git a/scripts/dev-setup.sh b/scripts/dev-setup.sh
new file mode 100755
index 0000000..1931634
--- /dev/null
+++ b/scripts/dev-setup.sh
@@ -0,0 +1,294 @@
+#!/usr/bin/env bash
+# Developer Onboarding Script for Local Development Setup
+# Automates the VeriNode Core development environment bootstrap.
+#
+# Usage:
+#   scripts/dev-setup.sh          # Full interactive setup
+#   scripts/dev-setup.sh --check  # Dry-run: validate prerequisites only
+#   scripts/dev-setup.sh --quick  # Skip slow verification steps
+#
+# Closes #85
+
+set -euo pipefail
+
+# --- Colour helpers -----------------------------------------------------------
+RED='\033[0;31m'
+GREEN='\033[0;32m'
+YELLOW='\033[1;33m'
+CYAN='\033[0;36m'
+NC='\033[0m' # No Colour
+
+info()    { printf "${CYAN}[INFO]${NC}    %s\n" "$*"; }
+success() { printf "${GREEN}[OK]${NC}      %s\n" "$*"; }
+warn()    { printf "${YELLOW}[WARN]${NC}    %s\n" "$*"; }
+fail()    { printf "${RED}[FAIL]${NC}    %s\n" "$*" >&2; }
+
+banner() {
+  cat <<'BANNER'
+╔══════════════════════════════════════════════════════════════════╗
+║        VeriNode Core – Developer Onboarding Setup               ║
+║        Decentralized ROSCA Protocol on Stellar Soroban          ║
+╚══════════════════════════════════════════════════════════════════╝
+BANNER
+}
+
+# --- Configuration ------------------------------------------------------------
+RUST_TOOLCHAIN="stable"
+WASM_TARGET="wasm32-unknown-unknown"
+MIN_RUSTC_VERSION="1.78.0"
+SOROBAN_CLI_VERSION="21.0.0"
+COVERAGE_THRESHOLD="80"
+
+MODE="${1:---full}"
+CHECK_ONLY=false
+QUICK=false
+
+case "$MODE" in
+  --check) CHECK_ONLY=true ;;
+  --quick) QUICK=true ;;
+  --full)  ;;
+  -h|--help)
+    echo "Usage: $0 [--check|--quick|--full|--help]"
+    exit 0
+    ;;
+  *) echo "Unknown option: $MODE"; exit 2 ;;
+esac
+
+repo_root="$(cd "$(dirname "$0")/.." && pwd)"
+cd "$repo_root"
+
+# --- Step 1: Rust toolchain ---------------------------------------------------
+check_rust() {
+  info "Checking Rust toolchain..."
+
+  if ! command -v rustc &>/dev/null; then
+    fail "rustc not found. Install Rust via https://rustup.rs"
+    if ! $CHECK_ONLY; then
+      info "Attempting automatic installation via rustup..."
+      curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh -s -- -y --default-toolchain "$RUST_TOOLCHAIN"
+      # shellcheck source=/dev/null
+      source "$HOME/.cargo/env"
+    fi
+    return 1
+  fi
+
+  local version
+  version="$(rustc --version | awk '{print $2}')"
+  if ! printf '%s\n%s\n' "$MIN_RUSTC_VERSION" "$version" | sort -V -C 2>/dev/null; then
+    warn "rustc $version is older than required minimum $MIN_RUSTC_VERSION"
+    if ! $CHECK_ONLY; then
+      info "Updating Rust toolchain..."
+      rustup update "$RUST_TOOLCHAIN"
+    fi
+  fi
+
+  success "rustc $version"
+}
+
+# --- Step 2: WASM target ------------------------------------------------------
+check_wasm_target() {
+  info "Checking WASM target ($WASM_TARGET)..."
+
+  if ! rustup target list --installed | grep -q "$WASM_TARGET"; then
+    warn "$WASM_TARGET not installed"
+    if ! $CHECK_ONLY; then
+      info "Adding $WASM_TARGET target..."
+      rustup target add "$WASM_TARGET"
+    fi
+    return 1
+  fi
+
+  success "$WASM_TARGET installed"
+}
+
+# --- Step 3: LLVM tools (coverage) --------------------------------------------
+check_llvm_tools() {
+  info "Checking llvm-tools-preview (coverage)..."
+
+  if ! rustup component list --installed | grep -q "llvm-tools-preview"; then
+    warn "llvm-tools-preview not installed"
+    if ! $CHECK_ONLY; then
+      info "Adding llvm-tools-preview component..."
+      rustup component add llvm-tools-preview
+    fi
+    return 1
+  fi
+
+  success "llvm-tools-preview installed"
+}
+
+# --- Step 4: cargo-llvm-cov ---------------------------------------------------
+check_cargo_llvm_cov() {
+  info "Checking cargo-llvm-cov..."
+
+  if ! command -v cargo-llvm-cov &>/dev/null; then
+    warn "cargo-llvm-cov not found"
+    if ! $CHECK_ONLY; then
+      info "Installing cargo-llvm-cov..."
+      cargo install cargo-llvm-cov
+    fi
+    return 1
+  fi
+
+  success "cargo-llvm-cov available"
+}
+
+# --- Step 5: Soroban CLI ------------------------------------------------------
+check_soroban_cli() {
+  info "Checking Soroban CLI..."
+
+  if command -v soroban &>/dev/null; then
+    local soroban_ver
+    soroban_ver="$(soroban --version 2>/dev/null | head -1 || echo 'unknown')"
+    success "soroban CLI: $soroban_ver"
+  else
+    warn "soroban CLI not found (optional – needed for contract deployment)"
+    info "Install via: cargo install soroban-cli --version $SOROBAN_CLI_VERSION"
+  fi
+}
+
+# --- Step 6: Cargo build ------------------------------------------------------
+cargo_build() {
+  if $CHECK_ONLY; then
+    info "Skipping build (--check mode)"
+    return 0
+  fi
+
+  info "Building project..."
+  cargo build --target "$WASM_TARGET" --release 2>&1 | tail -3
+
+  if [ "${PIPESTATUS[0]}" -eq 0 ]; then
+    success "Build succeeded"
+  else
+    fail "Build failed – check output above"
+    return 1
+  fi
+}
+
+# --- Step 7: Run tests --------------------------------------------------------
+cargo_test() {
+  if $CHECK_ONLY; then
+    info "Skipping tests (--check mode)"
+    return 0
+  fi
+
+  if $QUICK; then
+    info "Running quick test suite (--lib only)..."
+    cargo test --lib
+  else
+    info "Running full test suite..."
+    cargo test --verbose
+  fi
+
+  if [ "${PIPESTATUS[0]}" -eq 0 ]; then
+    success "All tests pass"
+  else
+    fail "Some tests failed – check output above"
+    return 1
+  fi
+}
+
+# --- Step 8: Coverage check ---------------------------------------------------
+cargo_coverage() {
+  if $CHECK_ONLY || $QUICK; then
+    info "Skipping coverage ($MODE mode)"
+    return 0
+  fi
+
+  info "Checking code coverage (threshold: ${COVERAGE_THRESHOLD}%)..."
+
+  if ! command -v cargo-llvm-cov &>/dev/null; then
+    warn "cargo-llvm-cov not available – skipping coverage"
+    return 0
+  fi
+
+  cargo llvm-cov clean --workspace 2>/dev/null || true
+  cargo llvm-cov --workspace \
+    --all-targets \
+    --locked \
+    --fail-under-lines "$COVERAGE_THRESHOLD" \
+    --summary-only 2>&1
+
+  if [ "${PIPESTATUS[0]}" -eq 0 ]; then
+    success "Coverage meets threshold (>= ${COVERAGE_THRESHOLD}%)"
+  else
+    warn "Coverage below ${COVERAGE_THRESHOLD}% – please add tests"
+  fi
+}
+
+# --- Step 9: Pre-commit hooks -------------------------------------------------
+setup_pre_commit() {
+  if $CHECK_ONLY; then
+    info "Skipping pre-commit setup (--check mode)"
+    return 0
+  fi
+
+  info "Setting up pre-commit hooks..."
+
+  if command -v pre-commit &>/dev/null; then
+    pre-commit install --install-hooks 2>&1 | tail -3
+    success "Pre-commit hooks installed"
+  else
+    warn "pre-commit not found – install with: pip install pre-commit"
+    warn "Then run: pre-commit install --install-hooks"
+  fi
+}
+
+# --- Step 10: Summary ---------------------------------------------------------
+print_summary() {
+  echo ""
+  echo "═══════════════════════════════════════════════════════════"
+  echo "  VeriNode Core – Developer Setup Complete"
+  echo "═══════════════════════════════════════════════════════════"
+  echo ""
+  echo "  Quick reference commands:"
+  echo "    cargo build --target $WASM_TARGET --release"
+  echo "    cargo test"
+  echo "    cargo llvm-cov --workspace --all-targets --locked --fail-under-lines $COVERAGE_THRESHOLD --summary-only"
+  echo "    scripts/pre-commit-quality.sh rustfmt src/lib.rs"
+  echo ""
+  echo "  See docs/ for architecture details and README.md for"
+  echo "  project overview."
+  echo ""
+  success "Onboarding complete! Happy coding."
+}
+
+# --- Main ---------------------------------------------------------------------
+main() {
+  banner
+  echo ""
+
+  local failures=0
+
+  check_rust          || ((failures++))
+  check_wasm_target   || ((failures++))
+  check_llvm_tools    || ((failures++))
+  check_cargo_llvm_cov || ((failures++))
+  check_soroban_cli   # optional
+
+  echo ""
+
+  if $CHECK_ONLY; then
+    if [ "$failures" -gt 0 ]; then
+      fail "$failures prerequisite(s) missing"
+      info "Run without --check to auto-install"
+      exit 1
+    fi
+    success "All prerequisites satisfied"
+    exit 0
+  fi
+
+  cargo_build   || ((failures++))
+  cargo_test    || ((failures++))
+  cargo_coverage || ((failures++))
+  setup_pre_commit
+
+  print_summary
+
+  if [ "$failures" -gt 0 ]; then
+    fail "$failures step(s) failed – see output above"
+    exit 1
+  fi
+}
+
+main
diff --git a/src/lib.rs b/src/lib.rs
index c0d97a6..63eca56 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -55,6 +55,16 @@ pub mod backup;
 // exponential-backoff retry and verified via BLS signature checks.
 pub mod webhook;
 
+// Runtime configuration auditing and drift detection.
+// Compares approved baselines with runtime snapshots to detect
+// unexpected changes during blue-green or canary rollout gates.
+pub mod config_audit;
+
+// Multi-region replication and disaster-recovery primitives (issue #91).
+// Dependency-free topology management with failover planning,
+// canary analysis, and DR-test reporting.
+pub mod replication;
+
 // --- ERROR CODES ---
 
 #[contracterror]