Add Nix flake for mciasctl and mciasgrpcctl

Vendor dependencies and expose control program binaries via
nix build. Uses nixpkgs-unstable for Go 1.26 support.

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

vendor/github.com/google/go-tpm/tpm2/transport/tpm.go

@@ -0,0 +1,90 @@
+// Package transport implements types for physically talking to TPMs.
+package transport
+
+import (
+	"io"
+
+	"github.com/google/go-tpm/tpmutil"
+)
+
+// TPM represents a logical connection to a TPM.
+type TPM interface {
+	Send(input []byte) ([]byte, error)
+}
+
+// TPMCloser represents a logical connection to a TPM and you can close it.
+type TPMCloser interface {
+	TPM
+	io.Closer
+}
+
+// wrappedRW represents a struct that wraps an io.ReadWriter
+// to a transport.TPM to be compatible with tpmdirect.
+type wrappedRW struct {
+	transport io.ReadWriter
+}
+
+// wrappedRWC represents a struct that wraps an io.ReadWriteCloser
+// to a transport.TPM to be compatible with tpmdirect.
+type wrappedRWC struct {
+	transport io.ReadWriteCloser
+}
+
+// wrappedTPM represents a struct that wraps a transport.TPM's underlying
+// transport to use with legacy code that expects an io.ReadWriter.
+type wrappedTPM struct {
+	response []byte
+	tpm      TPM
+}
+
+// FromReadWriter takes in a io.ReadWriter and returns a
+// transport.TPM wrapping the io.ReadWriter.
+func FromReadWriter(rw io.ReadWriter) TPM {
+	return &wrappedRW{transport: rw}
+}
+
+// FromReadWriteCloser takes in a io.ReadWriteCloser and returns a
+// transport.TPMCloser wrapping the io.ReadWriteCloser.
+func FromReadWriteCloser(rwc io.ReadWriteCloser) TPMCloser {
+	return &wrappedRWC{transport: rwc}
+}
+
+// ToReadWriter takes in a transport TPM and returns an
+// io.ReadWriter wrapping the transport TPM.
+func ToReadWriter(tpm TPM) io.ReadWriter {
+	return &wrappedTPM{tpm: tpm}
+}
+
+// Read copies t.response into the p buffer and return the appropriate length.
+func (t *wrappedTPM) Read(p []byte) (int, error) {
+	n := copy(p, t.response)
+	t.response = t.response[n:]
+	if len(t.response) == 0 {
+		return n, io.EOF
+	}
+	return n, nil
+}
+
+// Write implements the io.ReadWriter interface.
+func (t *wrappedTPM) Write(p []byte) (n int, err error) {
+	t.response, err = t.tpm.Send(p)
+	if err != nil {
+		return 0, err
+	}
+	return len(p), nil
+}
+
+// Send implements the TPM interface.
+func (t *wrappedRW) Send(input []byte) ([]byte, error) {
+	return tpmutil.RunCommandRaw(t.transport, input)
+}
+
+// Send implements the TPM interface.
+func (t *wrappedRWC) Send(input []byte) ([]byte, error) {
+	return tpmutil.RunCommandRaw(t.transport, input)
+}
+
+// Close implements the TPM interface.
+func (t *wrappedRWC) Close() error {
+	return t.transport.Close()
+}