Initial commit: dial — interactive SSH host picker

A fast, read-only ~/.ssh/config picker that exec's the system ssh client.
Includes: static high-contrast picker with recency/frequency/name sort and
tag grouping, `dial keygen` (native ed25519/RSA + optional config entry), and
an optional offline YubiKey launch gate with one-time recovery codes.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Makefile

@@ -0,0 +1,36 @@
+VERSION ?= 0.1.0
+LDFLAGS := -s -w -X main.version=$(VERSION)
+GO      ?= go
+
+# Release targets: macOS Apple Silicon + Intel, Linux amd64 + arm64, Windows.
+PLATFORMS := darwin/arm64 darwin/amd64 linux/amd64 linux/arm64 windows/amd64
+
+.PHONY: build install test vet run dist clean
+
+build: ## Build a native binary into ./bin/dial
+	$(GO) build -trimpath -ldflags "$(LDFLAGS)" -o bin/dial ./cmd/dial
+
+install: ## Install dial into $GOBIN / $GOPATH/bin
+	$(GO) install -trimpath -ldflags "$(LDFLAGS)" ./cmd/dial
+
+test: ## Run tests
+	$(GO) test ./...
+
+vet: ## Run go vet
+	$(GO) vet ./...
+
+run: build ## Build and run
+	./bin/dial
+
+dist: ## Cross-compile all release binaries into ./dist
+	@mkdir -p dist
+	@for p in $(PLATFORMS); do \
+		os=$${p%/*}; arch=$${p#*/}; ext=""; \
+		[ "$$os" = "windows" ] && ext=".exe"; \
+		echo "building dial-$$os-$$arch$$ext"; \
+		GOOS=$$os GOARCH=$$arch $(GO) build -trimpath -ldflags "$(LDFLAGS)" \
+			-o dist/dial-$$os-$$arch$$ext ./cmd/dial || exit 1; \
+	done
+
+clean: ## Remove build artifacts
+	rm -rf bin dist