Fix backup feature for local Windows development

- Add --no-reload flag to run_dev.py to prevent env var loss
- Configure SHOPDB_BACKUPS_ROOT in .env for Windows path
- Create local backups directory
- Document local dev setup in backup README
- Fix: Flask auto-reloader was spawning process without env vars

run_dev.py

@@ -0,0 +1,22 @@
+#!/usr/bin/env python
+"""
+Development server launcher for ShopDB.
+Loads .env file and starts Flask development server.
+"""
+import os
+import sys
+from pathlib import Path
+
+# Load .env BEFORE importing anything from Flask
+from dotenv import load_dotenv
+env_path = Path(__file__).parent / '.env'
+load_dotenv(env_path)
+
+print("Starting ShopDB Flask development server...")
+print(f"DATABASE_URL: {os.environ.get('DATABASE_URL', 'NOT SET')[:60]}...")
+print(f"SHOPDB_BACKUPS_ROOT: {os.environ.get('SHOPDB_BACKUPS_ROOT', 'NOT SET')}")
+
+# Import and run Flask (--no-reload so env vars don't get lost)
+from flask.cli import main as flask_main
+sys.argv = ['flask', 'run', '--host=0.0.0.0', '--port=5001', '--no-reload']
+flask_main()