feat: use DOCKER_IMAGE from .env in Makefile

- Update Makefile to read DOCKER_IMAGE from .env file with proper precedence
- Environment variables override .env file values
- Fallback to 'meds-app:latest' if not defined anywhere
- Add new Docker targets: docker-run, docker-push, docker-config
- Improve help output with environment variable documentation
- Update APP_NAME_CONFIGURATION.md to show Makefile usage examples

Variable precedence:
1. Environment variable (highest)
2. .env file (medium)
3. Default fallback (lowest)

Makefile

@@ -1,5 +1,15 @@
 # Makefile for Medication Reminder App
 
+# Check if DOCKER_IMAGE is set in environment, otherwise use .env or default
+ifndef DOCKER_IMAGE
+  # Include environment variables from .env file if it exists
+  -include .env
+  # Set default if still not defined
+  DOCKER_IMAGE ?= meds-app:latest
+endif
+
+export
+
 .PHONY: help install clean dev build test docker-build docker-clean
 
 # Default target
@@ -8,6 +18,12 @@
 ##@ General
 
 help: ## Display available commands
+	@echo "Medication Reminder App - Make Commands"
+	@echo ""
+	@echo "Environment Variables:"
+	@echo "  DOCKER_IMAGE         Docker image name (default: meds-app:latest)"
+	@echo "                       Can be set in .env file or environment"
+	@echo ""
 	@awk 'BEGIN {FS = ":.*##"} /^[a-zA-Z_0-9-]+:.*?##/ { printf "  %-20s %s\n", $$1, $$2 } /^##@/ { printf "\n%s\n", substr($$0, 5) } ' $(MAKEFILE_LIST)
 
 install: ## Install dependencies
@@ -41,16 +57,30 @@ test-watch: ## Run unit tests in watch mode
 ##@ Docker
 
 docker-build: ## Build Docker image for multiple architectures
-	@echo "Building multi-platform Docker image..."
+	@echo "Building multi-platform Docker image: $(DOCKER_IMAGE)"
 	@docker buildx build --platform linux/amd64,linux/arm64 \
 		--build-arg NODE_ENV=production \
-		-t meds-app:latest .
+		-t $(DOCKER_IMAGE) .
 
 docker-build-local: ## Build Docker image for local platform only
-	@echo "Building local Docker image..."
+	@echo "Building local Docker image: $(DOCKER_IMAGE)"
 	@docker buildx build --platform linux/amd64 \
 		--build-arg NODE_ENV=production \
-		-t meds-app:latest --load .
+		-t $(DOCKER_IMAGE) --load .
+
+docker-run: ## Run Docker container from built image
+	@echo "Running Docker container: $(DOCKER_IMAGE)"
+	@docker run --rm -p 8080:80 $(DOCKER_IMAGE)
+
+docker-push: ## Push Docker image to registry
+	@echo "Pushing Docker image: $(DOCKER_IMAGE)"
+	@docker push $(DOCKER_IMAGE)
+
+docker-config: ## Show current Docker configuration
+	@echo "Current Docker configuration:"
+	@echo "  DOCKER_IMAGE: $(DOCKER_IMAGE)"
+	@echo "  Available images:"
+	@docker images | grep -E "(REPOSITORY|$(shell echo $(DOCKER_IMAGE) | cut -d: -f1))" || true
 
 docker-clean: ## Clean Docker resources
 	@echo "Cleaning Docker resources..."