Fix ImageContent data encoding - use raw bytes not double-encoded base64

The MCP SDK handles base64 encoding during JSON marshaling, so the Data
field should contain raw binary data, not pre-encoded base64 strings.
This prevents double-encoding where base64 strings were being encoded again.

- Updated NewToolResultResourceWithFlag to pass raw binary data
- Updated test to verify raw binary data instead of base64 string
- Removed unused encoding/base64 imports

Co-authored-by: SamMorrowDrums <4811358+SamMorrowDrums@users.noreply.github.com>

Author: Copilot

pkg/utils/result.go

@@ -1,8 +1,6 @@
 package utils //nolint:revive //TODO: figure out a better name for this package
 
 import (
-	"encoding/base64"
-
 	"github.com/modelcontextprotocol/go-sdk/mcp"
 )
 
@@ -79,8 +77,9 @@ func NewToolResultResourceWithFlag(message string, contents *mcp.ResourceContent
 		}
 	case len(contents.Blob) > 0:
 		// Binary content - use ImageContent with base64 data
+		// Note: MCP SDK will handle base64 encoding during JSON marshaling
 		content = &mcp.ImageContent{
-			Data:     []byte(base64.StdEncoding.EncodeToString(contents.Blob)),
+			Data:     contents.Blob,
 			MIMEType: contents.MIMEType,
 			Meta: mcp.Meta{
 				"uri": contents.URI,

pkg/utils/result_test.go

@@ -1,7 +1,6 @@
 package utils //nolint:revive //TODO: figure out a better name for this package
 
 import (
-	"encoding/base64"
 	"testing"
 
 	"github.com/modelcontextprotocol/go-sdk/mcp"
@@ -90,9 +89,8 @@ func TestNewToolResultResourceWithFlag_EnabledFlag_BinaryContent(t *testing.T) {
 	imageContent, ok := result.Content[1].(*mcp.ImageContent)
 	require.True(t, ok, "Expected ImageContent but got %T", result.Content[1])
 
-	// Data should be base64 encoded
-	expectedBase64 := base64.StdEncoding.EncodeToString(binaryData)
-	assert.Equal(t, []byte(expectedBase64), imageContent.Data)
+	// Data should be raw binary (SDK handles base64 encoding during JSON marshaling)
+	assert.Equal(t, binaryData, imageContent.Data)
 	assert.Equal(t, "image/png", imageContent.MIMEType)
 	assert.NotNil(t, imageContent.Meta)
 	assert.Equal(t, "test://image.png", imageContent.Meta["uri"])