feat: добавить базовые сервисы image-platform

- добавлены backend, admin, gateway и worker skeleton
- добавлены Drizzle schema, database package и initial migration
- добавлены shared packages для RabbitMQ topology и S3 helpers
- обновлены dev-инфраструктура, env example, scripts и dependencies
- обновлена документация под versioned image URLs и read-through flow

.env.example

@@ -19,12 +19,39 @@ S3_SECRET_ACCESS_KEY=image-password
 S3_FORCE_PATH_STYLE=true
 
 # Future local services
-PUBLIC_API_BASE_URL=http://localhost:3001
+BACKEND_PORT=3001
+ADMIN_PORT=5173
+GATEWAY_HOST=0.0.0.0
+GATEWAY_PORT=8888
+PUBLIC_BACKEND_BASE_URL=http://localhost:3001
+PUBLIC_ADMIN_BASE_URL=http://localhost:5173
 PUBLIC_IMAGE_BASE_URL=http://localhost:8888
 
-# imgproxy is always external for image-platform.
-# Local example: run imgproxy separately on localhost:18080.
+# Gateway proxies /api and Swagger routes to this upstream.
+GATEWAY_BACKEND_UPSTREAM=http://localhost:3001
+
+# Dev imgproxy is exposed only on localhost.
+IMGPROXY_PORT=18080
 IMGPROXY_UPSTREAM=http://localhost:18080
 IMGPROXY_SIGNING_ENABLED=false
 IMGPROXY_KEY=
 IMGPROXY_SALT=
+IMGPROXY_WORKERS=2
+IMGPROXY_MAX_SRC_RESOLUTION=20
+IMGPROXY_DOWNLOAD_TIMEOUT=30
+IMGPROXY_ALLOWED_SOURCES=
+
+# RabbitMQ dev broker is exposed only on localhost.
+RABBITMQ_DEFAULT_USER=image
+RABBITMQ_DEFAULT_PASS=image-password
+RABBITMQ_DEFAULT_VHOST=image_platform
+RABBITMQ_PORT=5672
+RABBITMQ_MANAGEMENT_PORT=15672
+RABBITMQ_URL=amqp://image:image-password@localhost:5672/image_platform
+WORKER_PREFETCH=2
+
+# Queue topology
+RABBITMQ_JOBS_EXCHANGE=image-platform.jobs
+RABBITMQ_GENERATE_VARIANT_QUEUE=image.generate-variant
+RABBITMQ_GENERATE_VARIANT_DLX=image-platform.jobs.dlx
+RABBITMQ_GENERATE_VARIANT_DLQ=image.generate-variant.dlq