Update admin seed validation and test harness

scripts/validate_admin_seed.sh

@@ -0,0 +1,20 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+DB_CONNECTION_STRING="${1:-}"
+
+if [ -z "$DB_CONNECTION_STRING" ]; then
+  echo "Usage: $0 <db-connection-string>" >&2
+  exit 1
+fi
+
+if ! command -v psql >/dev/null 2>&1; then
+  echo "psql is required." >&2
+  exit 1
+fi
+
+echo "Checking admin seed..."
+psql "$DB_CONNECTION_STRING" -Atc "SELECT username FROM admin_users WHERE username = 'admin';" | grep -qx 'admin'
+echo "Checking schema migrations..."
+psql "$DB_CONNECTION_STRING" -Atc "SELECT 1 FROM schema_migrations WHERE version = '003';" >/dev/null
+echo "Admin seed validation passed."