build(docker): add makefile for image build and clean

Author: tmeckel

Makefile

@@ -0,0 +1,19 @@
+IMAGE ?= opencode-cli
+TAG ?= dev
+IMAGE_REF := $(IMAGE):$(TAG)
+DOCKERFILE ?= Dockerfile
+CONTEXT ?= .
+OPENCODE_VERSION ?= latest
+
+.PHONY: build clean
+
+build:
+	docker build \
+		-t $(IMAGE_REF) \
+		-f $(DOCKERFILE) \
+		--build-arg OPENCODE_VERSION=$(OPENCODE_VERSION) \
+		$(CONTEXT)
+
+clean:
+	@echo "Removing image $(IMAGE_REF) if it exists..."
+	- docker image inspect $(IMAGE_REF) >/dev/null 2>&1 && docker rmi $(IMAGE_REF) || true