feat: PostgreSQL 17 вместо SQLite

pg + connect-pg-simple, async routes, docker-compose, скрипт setup-postgres.

Co-authored-by: Cursor <cursoragent@cursor.com>

scripts/setup-postgres-ubuntu.sh

@@ -0,0 +1,32 @@
+#!/bin/bash
+# PostgreSQL 17 на Ubuntu — пользователь и БД для магазина
+# Запуск: sudo bash scripts/setup-postgres-ubuntu.sh
+set -euo pipefail
+
+DB_USER="${DB_USER:-shop}"
+DB_PASS="${DB_PASS:-shop}"
+DB_NAME="${DB_NAME:-shop}"
+
+if ! command -v psql >/dev/null; then
+  echo "Установите PostgreSQL 17:"
+  echo "  apt install -y postgresql-17 postgresql-client-17"
+  exit 1
+fi
+
+sudo -u postgres psql -v ON_ERROR_STOP=1 <<EOF
+DO \$\$
+BEGIN
+  IF NOT EXISTS (SELECT FROM pg_roles WHERE rolname = '${DB_USER}') THEN
+    CREATE ROLE ${DB_USER} LOGIN PASSWORD '${DB_PASS}';
+  END IF;
+END
+\$\$;
+
+SELECT 'CREATE DATABASE ${DB_NAME} OWNER ${DB_USER}'
+WHERE NOT EXISTS (SELECT FROM pg_database WHERE datname = '${DB_NAME}')\gexec
+
+GRANT ALL PRIVILEGES ON DATABASE ${DB_NAME} TO ${DB_USER};
+EOF
+
+echo ""
+echo "DATABASE_URL=postgresql://${DB_USER}:${DB_PASS}@127.0.0.1:5432/${DB_NAME}"