Model the build on mozimo and target emily

- Makefile: PLATFORMS, tags :<commit> and :main, build-check with --pull.
- deploy.sh: push, guards, git pull --ff-only, optional --prune, image_tag.
- Replace .containerignore with .dockerignore.
- Add the opt-in image prune to the hops role.
- Tag the Caddyfile task so --skip-tags caddy works before DNS cutover.
- Trim comments and rewrite build and deploy text in plain prose.

Makefile

@@ -1,42 +1,30 @@
-# Hops n Grains — container image builds.
-#
-# Built with Podman/Buildah, not Docker, from the committed tree
-# (`git archive HEAD`) and tagged with that commit, so a deploy ships exactly
-# what git knows about. deploy.sh pushes first and refuses a dirty tree.
-
 COMMIT ?= $(shell git rev-parse --short HEAD)
 
-# The deploy host (emily) is aarch64, so that is the default target: the image
-# is built for the machine it runs on, not the one running make. Podman carries
-# no built-in QEMU (unlike docker buildx), so a foreign platform needs binfmt
-# handlers on this host — qemu-user-binfmt is installed here. Override with e.g.
-# `make build-production PLATFORM=linux/amd64`.
-PLATFORM ?= linux/arm64
-
+# emily is aarch64, so that is the default target. A foreign platform needs
+# the host's binfmt handlers, because podman has no built-in QEMU.
+PLATFORMS ?= linux/arm64
 IMAGE ?= registry.tanshu.com/hops
 
 .PHONY: build-production
-build-production: ## Build HEAD with podman, tag :$(COMMIT) + :latest, and push
-	@echo "==> podman build --platform $(PLATFORM) → $(IMAGE):$(COMMIT) + :latest"
+build-production: ## Build HEAD with podman, push :$(COMMIT) and :main
+	@echo "==> podman build --platform $(PLATFORMS) -> $(IMAGE):$(COMMIT) + :main"
 	@git archive --format=tar HEAD | podman build \
-		--platform $(PLATFORM) \
+		--platform $(PLATFORMS) \
 		--tag $(IMAGE):$(COMMIT) \
-		--tag $(IMAGE):latest \
-		--pull=always \
+		--tag $(IMAGE):main \
 		- || { \
-		echo "✗ podman build failed."; \
-		echo "  Cross-platform builds need binfmt on this host (podman has no built-in QEMU):"; \
-		echo "    sudo apt install qemu-user-binfmt  # or qemu-user-static"; \
+		echo "podman build failed."; \
+		echo "Cross-platform builds need binfmt on this host (podman has no built-in QEMU):"; \
+		echo "  sudo apt install qemu-user-static    # on an x86_64 host, for $(PLATFORMS)"; \
 		exit 1; \
 	}
 	podman push $(IMAGE):$(COMMIT)
-	podman push $(IMAGE):latest
+	podman push $(IMAGE):main
 
 .PHONY: build-check
 build-check: ## Compile check from HEAD with podman, nothing pushed
-	@echo "==> podman build --platform $(PLATFORM) (no push)"
-	git archive --format=tar HEAD | podman build \
-		--platform $(PLATFORM) \
-		--tag localhost/hops:check \
-		--pull=always \
+	@git archive --format=tar HEAD | podman build \
+		--platform $(PLATFORMS) \
+		--tag hops:check \
+		--pull \
 		-