Add example environment configuration and Docker Compose setup

- Introduced a new `.env.example` file to provide a template for environment variables used by the Scratchbox server.
- Added a `docker-compose.example.yml` file to facilitate easy deployment of the Scratchbox service with Docker.
- Updated `docker-entrypoint.sh` to enforce environment variable settings for server configuration.
- Removed the generation of a config key file from the workflow, simplifying the configuration process.
- Adjusted the README.md to reflect changes in configuration management and usage instructions.

Makefile

@@ -5,13 +5,12 @@ BIN := $(BIN_DIR)/$(APP_NAME)
 CONFIG ?= config.yaml
 DOCKER_IMAGE ?= scratchbox:dev
 
-.PHONY: help run dev config build docker test test-race fmt clean
+.PHONY: help run dev build docker test test-race fmt clean
 
 help:
 	@echo "Targets:"
 	@echo "  make run    - Alias for make dev"
 	@echo "  make dev    - Build and run server (CONFIG=$(CONFIG))"
-	@echo "  make config - Write default config to $(CONFIG) and generate sibling config.key if missing"
 	@echo "  make build  - Build Svelte UI and binary to $(BIN)"
 	@echo "  make docker - Build Docker image (DOCKER_IMAGE=$(DOCKER_IMAGE))"
 	@echo "  make test   - Run all Go tests with timeout and shuffle"
@@ -24,13 +23,6 @@ run: dev
 dev: build
 	$(BIN) server --config $(CONFIG)
 
-config:
-	mkdir -p "$(dir $(CONFIG))"
-	go run $(CMD_DIR) generate-config > "$(CONFIG)"
-	@if [ ! -f "$(dir $(CONFIG))config.key" ]; then \
-		go run $(CMD_DIR) generate-key > "$(dir $(CONFIG))config.key"; \
-	fi
-
 build: clean
 	npm --prefix ./web/ui run build
 	mkdir -p $(BIN_DIR)
@@ -49,4 +41,6 @@ fmt:
 	go fmt ./...
 
 clean:
+	rm -rf web/static
+	rm -rf $(CONFIG)
 	rm -rf $(BIN_DIR)