fix: configure PostgreSQL for production and clean up deployment

- Fix database configuration to use PostgreSQL in production
- Add knexfile.js to support both SQLite (dev) and PostgreSQL (prod)
- Create admin user creation script (scripts/create-admin.js)
- Clean up docker-compose files:
  - Remove redundant docker-compose.yml and docker-compose.local.yml
  - Create docker-compose.dev.yml for development
  - Update docker-compose.prod.yml with proper DB configuration
- Clean up environment files:
  - Update .env.example for development
  - Update .env.production.example with proper settings
  - Remove redundant .env.local
- Update backend .env.example with database configuration options
- Create comprehensive DEPLOYMENT.md with admin setup instructions
- Fix production database name consistency (picpeak instead of photoapp)

docker-compose.prod.yml

@@ -14,12 +14,21 @@ services:
       - JWT_SECRET=${JWT_SECRET}
       - ADMIN_URL=${ADMIN_URL}
       - FRONTEND_URL=${FRONTEND_URL}
+      # Database
+      - DATABASE_CLIENT=pg
+      - DB_HOST=db
+      - DB_PORT=5432
+      - DB_USER=${DB_USER:-picpeak}
+      - DB_PASSWORD=${DB_PASSWORD}
+      - DB_NAME=${DB_NAME:-picpeak}
+      # Email
       - SMTP_HOST=${SMTP_HOST}
       - SMTP_PORT=${SMTP_PORT}
       - SMTP_SECURE=${SMTP_SECURE}
       - SMTP_USER=${SMTP_USER}
       - SMTP_PASS=${SMTP_PASS}
       - EMAIL_FROM=${EMAIL_FROM}
+      # Analytics
       - UMAMI_URL=${UMAMI_URL}
       - UMAMI_WEBSITE_ID=${UMAMI_WEBSITE_ID}
     volumes:
@@ -70,7 +79,7 @@ services:
     image: postgres:14-alpine
     restart: unless-stopped
     environment:
-      - POSTGRES_USER=${DB_USER:-photoapp}
+      - POSTGRES_USER=${DB_USER:-picpeak}
       - POSTGRES_PASSWORD=${DB_PASSWORD}
       - POSTGRES_DB=${DB_NAME:-picpeak}
     volumes:
@@ -82,7 +91,7 @@ services:
     image: ghcr.io/umami-software/umami:postgresql-latest
     restart: unless-stopped
     environment:
-      DATABASE_URL: postgresql://${DB_USER:-photoapp}:${DB_PASSWORD}@db:5432/umami
+      DATABASE_URL: postgresql://${DB_USER:-picpeak}:${DB_PASSWORD}@db:5432/umami
       DATABASE_TYPE: postgresql
       HASH_SALT: ${UMAMI_HASH_SALT}
     depends_on: