Go Makefile (the inner loop)

Preserve the project's existing build tool and approved commands. When both Make and Task are already used, keep build/test/codegen recipes in Make and let [[z-go-taskfile]] delegate orchestration to them. Do not introduce a second tool solely to enforce this split.

Self-documenting help

Two conventions exist. Inline target: ## desc puts the comment on the target line itself:

.PHONY: help
help: ## show available targets
	@grep -E '^[a-zA-Z0-9_-]+:.*## ' $(MAKEFILE_LIST) | \
		awk 'BEGIN {FS = ":.*## "}; {printf "  %-15s %s\n", $$1, $$2}'

build: ## compile the main binary
	$(GO_BUILD) -o $(BUILD_DIR)/app ./cmd/app