feat: PostgreSQL 17 вместо SQLite

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

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

package.json

@@ -1,7 +1,7 @@
 {
   "name": "shop",
-  "version": "1.0.0",
-  "description": "Интернет-магазин на Node.js с локальной SQLite",
+  "version": "2.0.0",
+  "description": "Интернет-магазин на Node.js с PostgreSQL 17",
   "main": "src/server.js",
   "scripts": {
     "start": "node src/server.js",
@@ -13,10 +13,10 @@
   },
   "dependencies": {
     "bcryptjs": "^2.4.3",
-    "better-sqlite3": "^11.7.0",
-    "connect-sqlite3": "^0.9.15",
+    "connect-pg-simple": "^10.0.0",
     "ejs": "^3.1.10",
     "express": "^4.21.2",
-    "express-session": "^1.18.1"
+    "express-session": "^1.18.1",
+    "pg": "^8.13.1"
   }
 }