feat: bootstrap Go project layout (forgejo-mcp-broker-n84)

- Initialize go.mod with module path kode.naiv.no/olemd/forgejo-mcp-broker
- Create directory layout: cmd/broker + internal/{buildinfo,config,log,store,httpserver}
- Add Makefile with build/test/lint/tidy/clean targets and ldflags-injected build info
- Stub cmd/broker/main.go with --version support; real wiring follows in -t37
- Stub doc.go for each internal/* package, pointing to the issue that fills it in

Closes forgejo-mcp-broker-n84.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Makefile

@@ -0,0 +1,39 @@
+# forgejo-mcp-broker Makefile
+
+BINARY      := fjmcp-broker
+CMD_PKG     := ./cmd/broker
+MODULE      := kode.naiv.no/olemd/forgejo-mcp-broker
+VERSION     := $(shell git describe --tags --always --dirty 2>/dev/null || echo dev)
+GIT_REV     := $(shell git rev-parse --short HEAD 2>/dev/null || echo unknown)
+BUILD_DATE  := $(shell date -u +%Y-%m-%dT%H:%M:%SZ)
+LDFLAGS     := -s -w \
+               -X $(MODULE)/internal/buildinfo.Version=$(VERSION) \
+               -X $(MODULE)/internal/buildinfo.GitRevision=$(GIT_REV) \
+               -X $(MODULE)/internal/buildinfo.BuildDate=$(BUILD_DATE)
+
+.PHONY: all build test lint tidy clean help
+
+all: build
+
+build: ## Build the broker binary
+	go build -trimpath -ldflags '$(LDFLAGS)' -o $(BINARY) $(CMD_PKG)
+
+test: ## Run tests with the race detector
+	go test -race ./...
+
+lint: ## Static analysis (go vet; golangci-lint if installed)
+	go vet ./...
+	@if command -v golangci-lint >/dev/null 2>&1; then \
+		golangci-lint run; \
+	else \
+		echo "golangci-lint not installed; skipping (go vet already ran)"; \
+	fi
+
+tidy: ## Tidy go.mod / go.sum
+	go mod tidy
+
+clean: ## Remove build artefacts
+	rm -f $(BINARY)
+
+help: ## Show available targets
+	@awk 'BEGIN {FS = ":.*##"; print "Targets:"} /^[a-zA-Z_-]+:.*?##/ { printf "  %-8s %s\n", $$1, $$2 }' $(MAKEFILE_LIST)