chore: добавить каркас image-platform

- добавлен базовый pnpm workspace для будущих приложений

- добавлена dev-инфраструктура PostgreSQL и MinIO

- добавлены env-пример и базовые правила репозитория

- зафиксированы архитектура, data model и API-контракт

- описан контракт с внешним imgproxy

.env.example

@@ -0,0 +1,30 @@
+# Local dev infrastructure
+POSTGRES_DB=image_platform
+POSTGRES_USER=image
+POSTGRES_PASSWORD=image-password
+POSTGRES_PORT=5433
+DATABASE_URL=postgres://image:image-password@localhost:5433/image_platform
+
+MINIO_ROOT_USER=image
+MINIO_ROOT_PASSWORD=image-password
+MINIO_API_PORT=9000
+MINIO_CONSOLE_PORT=9001
+
+S3_ENDPOINT=http://localhost:9000
+S3_INTERNAL_ENDPOINT=http://minio:9000
+S3_REGION=us-east-1
+S3_BUCKET=image-platform
+S3_ACCESS_KEY_ID=image
+S3_SECRET_ACCESS_KEY=image-password
+S3_FORCE_PATH_STYLE=true
+
+# Future local services
+PUBLIC_API_BASE_URL=http://localhost:3001
+PUBLIC_IMAGE_BASE_URL=http://localhost:8888
+
+# imgproxy is always external for image-platform.
+# Local example: run imgproxy separately on localhost:18080.
+IMGPROXY_UPSTREAM=http://localhost:18080
+IMGPROXY_SIGNING_ENABLED=false
+IMGPROXY_KEY=
+IMGPROXY_SALT=