Standardize Makefile docker/push targets for MCR

Add MCR and VERSION variables. Tag images with full MCR registry URL
and version. Add push target that builds then pushes to MCR.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Makefile

@@ -1,6 +1,8 @@
-.PHONY: build test vet lint clean docker all devserver
+.PHONY: build test vet lint clean docker push all devserver
 
-LDFLAGS := -trimpath -ldflags="-s -w -X main.version=$(shell git describe --tags --always --dirty)"
+MCR     := mcr.svc.mcp.metacircular.net:8443
+VERSION := $(shell git describe --tags --always --dirty)
+LDFLAGS := -trimpath -ldflags="-s -w -X main.version=$(VERSION)"
 
 mcdoc:
 	CGO_ENABLED=0 go build $(LDFLAGS) -o mcdoc ./cmd/mcdoc
@@ -21,7 +23,10 @@ clean:
 	rm -f mcdoc
 
 docker:
-	docker build --build-arg VERSION=$(shell git describe --tags --always --dirty) -t mcdoc -f Dockerfile .
+	docker build --build-arg VERSION=$(VERSION) -t $(MCR)/mcdoc:$(VERSION) -f Dockerfile .
+
+push: docker
+	docker push $(MCR)/mcdoc:$(VERSION)
 
 devserver: mcdoc
 	@mkdir -p srv