Automate SAM download and fix database path issues

- Fix database path mismatch: download_sample_eyes.py now uses
  ai_photo_edit.db instead of photoedit.db
- Add init_database.py script to initialize DB before eye import
- Add AUTO_DOWNLOAD_SAM=true environment variable (default: enabled)
- Update entrypoint.sh to:
  1. Initialize database first
  2. Auto-download SAM model (~375MB) on first startup
  3. Then import eyes (now works since DB exists)
- Update path detection to work in both Docker and local environments

docker-compose.yml

@@ -20,6 +20,7 @@ services:
       - STABILITY_API_KEY=${STABILITY_API_KEY:-}
       - REPLICATE_API_KEY=${REPLICATE_API_KEY:-}
       - CORS_ORIGINS=http://localhost:5173,http://localhost:3000,http://localhost
+      - AUTO_DOWNLOAD_SAM=${AUTO_DOWNLOAD_SAM:-true}
     restart: unless-stopped
     networks:
       - ai-photo-edit-network