feat: funciones SSH para infra — conn, check, exec, download, upload, tunnel

Conjunto completo de funciones SSH para operaciones remotas: conexión,
verificación de host, ejecución de comandos, transferencia de archivos
(upload/download) y gestión de túneles. Incluye tipo SSHConn y tests.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

functions/infra/ssh_conn_test.go

@@ -0,0 +1,73 @@
+package infra
+
+import (
+	"testing"
+)
+
+func TestSSHConnDestination(t *testing.T) {
+	tests := []struct {
+		name string
+		conn SSHConn
+		want string
+	}{
+		{"con user", SSHConn{Host: "example.com", User: "deploy"}, "deploy@example.com"},
+		{"sin user", SSHConn{Host: "example.com"}, "example.com"},
+		{"con IP", SSHConn{Host: "10.0.0.1", User: "root"}, "root@10.0.0.1"},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := tt.conn.destination()
+			if got != tt.want {
+				t.Errorf("destination() = %q, want %q", got, tt.want)
+			}
+		})
+	}
+}
+
+func TestSSHConnSSHArgs(t *testing.T) {
+	t.Run("puerto default", func(t *testing.T) {
+		conn := SSHConn{Host: "example.com", User: "deploy"}
+		args := conn.sshArgs()
+		assertContains(t, args, "-p", "22")
+	})
+
+	t.Run("puerto custom", func(t *testing.T) {
+		conn := SSHConn{Host: "example.com", Port: 2222}
+		args := conn.sshArgs()
+		assertContains(t, args, "-p", "2222")
+	})
+
+	t.Run("con key path", func(t *testing.T) {
+		conn := SSHConn{Host: "example.com", KeyPath: "/home/user/.ssh/id_ed25519"}
+		args := conn.sshArgs()
+		assertContains(t, args, "-i", "/home/user/.ssh/id_ed25519")
+	})
+
+	t.Run("sin key path no incluye -i", func(t *testing.T) {
+		conn := SSHConn{Host: "example.com"}
+		args := conn.sshArgs()
+		for _, a := range args {
+			if a == "-i" {
+				t.Error("sshArgs() no debe incluir -i si KeyPath esta vacio")
+			}
+		}
+	})
+}
+
+func TestSSHConnSCPArgs(t *testing.T) {
+	t.Run("usa -P mayuscula para puerto", func(t *testing.T) {
+		conn := SSHConn{Host: "example.com", Port: 2222}
+		args := conn.scpArgs()
+		assertContains(t, args, "-P", "2222")
+	})
+}
+
+func assertContains(t *testing.T, args []string, flag, value string) {
+	t.Helper()
+	for i, a := range args {
+		if a == flag && i+1 < len(args) && args[i+1] == value {
+			return
+		}
+	}
+	t.Errorf("args %v no contiene %s %s", args, flag, value)
+}