fix: align WAL multi-surface DB safety

- align app and standalone MCP busy-timeout and retry behavior
- guard live DB dev and restore flows
- document WAL maintenance boundaries

scripts/dev/guard-live-db-dev.sh

@@ -0,0 +1,37 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+ROOT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")/../.." && pwd)"
+DEFAULT_DB="$HOME/Library/Application Support/RA-H/db/rah.sqlite"
+
+DB_PATH="${SQLITE_DB_PATH:-}"
+if [ -z "$DB_PATH" ] && [ -f "${ROOT_DIR}/.env.local" ]; then
+  DB_PATH=$(grep -E '^SQLITE_DB_PATH=' "${ROOT_DIR}/.env.local" | sed 's/^SQLITE_DB_PATH=//' | sed 's/^"\(.*\)"$/\1/') || true
+fi
+if [ -z "$DB_PATH" ]; then
+  DB_PATH="$DEFAULT_DB"
+fi
+
+if [ "$DB_PATH" != "$DEFAULT_DB" ]; then
+  exit 0
+fi
+
+echo "⚠️  dev:mac is using the packaged live RA-H DB:"
+echo "   $DB_PATH"
+echo "   Prefer SQLITE_DB_PATH=<dev-db> for isolated development when possible."
+
+owners="$("${ROOT_DIR}/scripts/database/rah-db-owners.sh" "$DB_PATH" || true)"
+if [ -z "$owners" ]; then
+  exit 0
+fi
+
+if [ "${RAH_ALLOW_LIVE_DB_DEV:-}" = "true" ]; then
+  echo "RAH_ALLOW_LIVE_DB_DEV=true set; continuing despite live DB owners:"
+  echo "$owners" | sed 's/^/  /'
+  exit 0
+fi
+
+echo "❌ Refusing to start dev server against the live DB while these processes have it open:"
+echo "$owners" | sed 's/^/  /'
+echo "Close RA-H/MCP owners first, set SQLITE_DB_PATH to a dev DB, or override with RAH_ALLOW_LIVE_DB_DEV=true."
+exit 1