Initial implementation: NATS->S3 archiver + search/retrieve CLI

logarchiver replaces the plain Vector archiver leg of the centralized
logging stack (argocd-apps #296) with a Go service that archives raw logs
from NATS JetStream to S3 as zstd-compressed, OpenPGP-encrypted, indexed
objects, plus an operator CLI to search the index and retrieve/decrypt
archived logs. It adds the things that outgrew Vector: zstd compression,
encryption keyed from Ben's Vault GPG secrets engine, a searchable
ClickHouse index, and sink-conditional acks (a batch is acknowledged to
JetStream only after the object is durably in S3 AND indexed).

Service (`logarchiver run`):
- Durable JetStream pull consumer (stream LOGS, durable archiver, subject
  filter default logs.k8s.vault.>), explicit acks, independent offsets.
- Batch per subject by size/count/time -> NDJSON -> zstd -> encrypt -> S3
  PUT -> ClickHouse index row -> ack. On any failure the batch is Nak'd and
  redelivered, so nothing is lost on a sink outage.
- Encryption is a wrapped-DEK envelope (container LARC1): the bulk is
  AES-256-GCM framed under a random data key, and only that 32-byte key is
  OpenPGP-encrypted to the engine's public key. This is because the Vault
  GPG engine does whole-payload decrypt only; retrieval round-trips just the
  tiny wrapped key regardless of object size. Public key fetched from the
  engine or a mounted file (configurable); key fingerprint recorded per
  object; periodic pubkey refresh for rotation.
- Prometheus metrics, structured slog, graceful drain on shutdown.

CLI:
- `search` queries the index (subject/host/time) and lists matching objects.
- `fetch` downloads, decrypts via the Vault GPG engine, unzstds and emits
  NDJSON (optionally re-filtered by host/time).
- `init-schema` creates/prints the ClickHouse archive_index DDL.
- cobra `completion` subcommands.

Config via file+env (k8s-friendly, secrets from env), boundaries (NATS/S3/
ClickHouse/Vault) behind interfaces with unit tests (config, batching,
host/subject extraction, crypto roundtrip with a test key, ack-after-persist
with fakes, search query building). go build/vet/test -race clean;
golangci-lint v2 clean. Woodpecker CI: build/test/pre-commit on PR; on v*
tag a container image plus a Gitea binary release + rpm-internal RPM. Docs
per subcommand + architecture + retrieval runbook + deployment drop-in.

Claude-Session: https://claude.ai/code/session_015ur3i7D2azsMAWTSVABApv

Makefile

@@ -0,0 +1,81 @@
+BINARY  := logarchiver
+PKG     := ./cmd/logarchiver
+DIST    := dist
+MODULE  := git.unkin.net/unkin/logarchiver
+VERSION := $(shell git describe --tags --always --dirty 2>/dev/null || echo dev)
+GOFLAGS := -ldflags="-s -w -X main.version=$(VERSION)"
+OS      ?= $(shell go env GOOS)
+ARCH    ?= $(shell go env GOARCH)
+
+GO_VERSION_REQUIRED := 1.23
+GO_VERSION_ACTUAL := $(shell go version | sed 's/go version go\([0-9]*\.[0-9]*\).*/\1/')
+
+.PHONY: all build test test-race lint fmt vet tidy clean install completions rpm rpm-package check-go patch minor major _tag
+
+all: build
+
+check-go:
+	@if [ "$$(printf '%s\n%s' "$(GO_VERSION_REQUIRED)" "$(GO_VERSION_ACTUAL)" | sort -V | head -1)" != "$(GO_VERSION_REQUIRED)" ]; then \
+		echo "ERROR: Go >= $(GO_VERSION_REQUIRED) required, found $(GO_VERSION_ACTUAL)"; exit 1; \
+	fi
+
+# Build the single logarchiver binary (service + CLI) into dist/.
+build: check-go tidy
+	CGO_ENABLED=0 GOOS=$(OS) GOARCH=$(ARCH) go build $(GOFLAGS) -o $(DIST)/$(BINARY) $(PKG)
+
+test: check-go
+	go test -race -count=1 ./...
+
+test-race: test
+
+lint:
+	golangci-lint run ./...
+
+vet:
+	go vet ./...
+
+fmt:
+	gofmt -w .
+
+tidy:
+	go mod tidy
+
+install:
+	go install $(GOFLAGS) $(PKG)
+
+clean:
+	rm -rf $(DIST) $(BINARY) $(BINARY)-*
+
+# Generate bash/zsh/fish completions from the freshly built binary.
+completions: build
+	@mkdir -p $(DIST)/completions
+	$(DIST)/$(BINARY) completion bash > $(DIST)/completions/$(BINARY).bash
+	$(DIST)/$(BINARY) completion zsh  > $(DIST)/completions/_$(BINARY)
+	$(DIST)/$(BINARY) completion fish > $(DIST)/completions/$(BINARY).fish
+
+# Build then package the CLI into an RPM (with completions) via nfpm.
+rpm: build rpm-package
+rpm-package:
+	./scripts/build-rpm.sh $(VERSION)
+
+# Bump helpers — read the latest semver tag and create/push the next one.
+_LATEST := $(shell git tag --sort=-v:refname | grep -E '^v[0-9]+\.[0-9]+\.[0-9]+$$' | head -1)
+_BASE   := $(if $(_LATEST),$(_LATEST),v0.0.0)
+_MAJ    := $(shell echo $(_BASE) | sed 's/^v//' | cut -d. -f1)
+_MIN    := $(shell echo $(_BASE) | sed 's/^v//' | cut -d. -f2)
+_PAT    := $(shell echo $(_BASE) | sed 's/^v//' | cut -d. -f3)
+
+patch:
+	@NEW=v$(_MAJ).$(_MIN).$(shell expr $(_PAT) + 1); \
+	git tag $$NEW && echo "Tagged $$NEW" && $(MAKE) _tag TAG=$$NEW
+
+minor:
+	@NEW=v$(_MAJ).$(shell expr $(_MIN) + 1).0; \
+	git tag $$NEW && echo "Tagged $$NEW" && $(MAKE) _tag TAG=$$NEW
+
+major:
+	@NEW=v$(shell expr $(_MAJ) + 1).0.0; \
+	git tag $$NEW && echo "Tagged $$NEW" && $(MAKE) _tag TAG=$$NEW
+
+_tag:
+	git push origin $(TAG)