feat: migrate from msgpack to protobuf (handler-base v1.0.0)

- Replace msgpack.Marshal with proto.Marshal
- Update field names to proto convention (SessionId, SpeakerId)
- Cast Sequence to int32 for proto compatibility

main.go

@@ -20,7 +20,7 @@ import (
 	"time"
 
 	"github.com/nats-io/nats.go"
-	"github.com/vmihailenco/msgpack/v5"
+	"google.golang.org/protobuf/proto"
 
 	"git.daviestechlabs.io/daviestechlabs/handler-base/config"
 	"git.daviestechlabs.io/daviestechlabs/handler-base/health"
@@ -324,17 +324,17 @@ func main() {
 
 		if transcript != "" {
 			result := &messages.STTTranscription{
-				SessionID:        sessionID,
+				SessionId:        sessionID,
 				Transcript:       transcript,
-				Sequence:         seq,
+				Sequence:         int32(seq),
 				IsPartial:        !complete,
 				IsFinal:          complete,
 				Timestamp:        time.Now().Unix(),
-				SpeakerID:        speakerID,
+				SpeakerId:        speakerID,
 				HasVoiceActivity: hasVoice,
 				State:            state,
 			}
-			packed, _ := msgpack.Marshal(result)
+			packed, _ := proto.Marshal(result)
 			_ = nc.Conn().Publish(fmt.Sprintf("%s.%s", transcriptionSubjectPrefix, sessionID), packed)
 			slog.Info("published transcription", "session", sessionID, "seq", seq)
 		}
@@ -378,8 +378,8 @@ func main() {
 		}
 		sessionID := parts[3]
 
-		streamMsg, err := natsutil.Decode[messages.STTStreamMessage](natMsg.Data)
-		if err != nil {
+		var streamMsg messages.STTStreamMessage
+		if err := natsutil.Decode(natMsg.Data, &streamMsg); err != nil {
 			slog.Error("decode error", "error", err)
 			return
 		}
@@ -391,8 +391,8 @@ func main() {
 			if streamMsg.State != "" {
 				buf.setState(streamMsg.State)
 			}
-			if streamMsg.SpeakerID != "" {
-				buf.speakerID = streamMsg.SpeakerID
+			if streamMsg.SpeakerId != "" {
+				buf.speakerID = streamMsg.SpeakerId
 			}
 			sessionsMu.Lock()
 			sessions[sessionID] = buf
@@ -442,12 +442,12 @@ func main() {
 			// Check for interrupt
 			if buffer.checkInterrupt(streamMsg.Audio, enableInterrupt, audioLevelThreshold, interruptDuration) {
 				interruptMsg := &messages.STTInterrupt{
-					SessionID: sessionID,
+					SessionId: sessionID,
 					Type:      "interrupt",
 					Timestamp: time.Now().Unix(),
-					SpeakerID: buffer.speakerID,
+					SpeakerId: buffer.speakerID,
 				}
-				packed, _ := msgpack.Marshal(interruptMsg)
+				packed, _ := proto.Marshal(interruptMsg)
 				_ = nc.Conn().Publish(fmt.Sprintf("%s.%s", transcriptionSubjectPrefix, sessionID), packed)
 				slog.Info("published interrupt", "session", sessionID)
 				buffer.setState(stateListening)