refactor: 重构trustlog-sdk目录结构到trustlog/go-trustlog

- 将所有trustlog-sdk文件移动到trustlog/go-trustlog/目录
- 更新README中所有import路径从trustlog-sdk改为go-trustlog
- 更新cookiecutter配置文件中的项目名称
- 更新根目录.lefthook.yml以引用新位置的配置
- 添加go.sum文件到版本控制
- 删除过时的示例文件

这次重构与trustlog-server保持一致的目录结构，
为未来支持多语言SDK（Python、Java等）预留空间。

api/model/signer_test.go

@@ -0,0 +1,135 @@
+package model_test
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
+	"go.yandata.net/iod/iod/trustlog-sdk/api/model"
+)
+
+func TestNewSM2Signer(t *testing.T) {
+	t.Parallel()
+
+	privateKey := []byte("test-private-key")
+	publicKey := []byte("test-public-key")
+
+	signer := model.NewSM2Signer(privateKey, publicKey)
+	assert.NotNil(t, signer)
+}
+
+func TestNewNopSigner(t *testing.T) {
+	t.Parallel()
+
+	signer := model.NewNopSigner()
+	assert.NotNil(t, signer)
+}
+
+func TestNopSigner_Sign(t *testing.T) {
+	t.Parallel()
+
+	signer := model.NewNopSigner()
+	data := []byte("test data")
+
+	result, err := signer.Sign(data)
+	require.NoError(t, err)
+	assert.Equal(t, data, result)
+	assert.NotSame(t, &data[0], &result[0]) // Should be a copy
+}
+
+func TestNopSigner_Sign_Empty(t *testing.T) {
+	t.Parallel()
+
+	signer := model.NewNopSigner()
+	data := []byte{}
+
+	result, err := signer.Sign(data)
+	require.NoError(t, err)
+	assert.Equal(t, data, result)
+}
+
+func TestNopSigner_Verify_Success(t *testing.T) {
+	t.Parallel()
+
+	signer := model.NewNopSigner()
+	data := []byte("test data")
+	signature := []byte("test data") // Same as data
+
+	valid, err := signer.Verify(data, signature)
+	require.NoError(t, err)
+	assert.True(t, valid)
+}
+
+func TestNopSigner_Verify_Failure(t *testing.T) {
+	t.Parallel()
+
+	signer := model.NewNopSigner()
+	data := []byte("test data")
+	signature := []byte("different data")
+
+	valid, err := signer.Verify(data, signature)
+	require.NoError(t, err)
+	assert.False(t, valid)
+}
+
+func TestNopSigner_RoundTrip(t *testing.T) {
+	t.Parallel()
+
+	signer := model.NewNopSigner()
+	data := []byte("test data")
+
+	signature, err := signer.Sign(data)
+	require.NoError(t, err)
+
+	valid, err := signer.Verify(data, signature)
+	require.NoError(t, err)
+	assert.True(t, valid)
+}
+
+func TestNopSigner_Verify_DifferentLengths(t *testing.T) {
+	t.Parallel()
+
+	signer := model.NewNopSigner()
+
+	tests := []struct {
+		name      string
+		data      []byte
+		signature []byte
+		expected  bool
+	}{
+		{
+			name:      "same data",
+			data:      []byte("test"),
+			signature: []byte("test"),
+			expected:  true,
+		},
+		{
+			name:      "different data",
+			data:      []byte("test"),
+			signature: []byte("test2"),
+			expected:  false,
+		},
+		{
+			name:      "different lengths",
+			data:      []byte("test"),
+			signature: []byte("test1"),
+			expected:  false,
+		},
+		{
+			name:      "empty",
+			data:      []byte{},
+			signature: []byte{},
+			expected:  true,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			t.Parallel()
+			valid, err := signer.Verify(tt.data, tt.signature)
+			require.NoError(t, err)
+			assert.Equal(t, tt.expected, valid)
+		})
+	}
+}