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

- Replace msgpack encoding with protobuf wire format
- Update field names to proto convention (UserId, RequestId, EnableRag, etc.)
- Use messages.EffectiveQuery() standalone function
- Cast TopK to int32 for proto compatibility
- Rewrite tests for proto round-trips

main.go

@@ -16,6 +16,7 @@ import (
 	"git.daviestechlabs.io/daviestechlabs/handler-base/handler"
 	"git.daviestechlabs.io/daviestechlabs/handler-base/messages"
 	"git.daviestechlabs.io/daviestechlabs/handler-base/natsutil"
+	"google.golang.org/protobuf/proto"
 )
 
 func main() {
@@ -45,23 +46,23 @@ func main() {
 
 	h := handler.New("ai.chat.user.*.message", cfg)
 
-	h.OnTypedMessage(func(ctx context.Context, msg *nats.Msg) (any, error) {
-		req, err := natsutil.Decode[messages.ChatRequest](msg.Data)
-		if err != nil {
+	h.OnTypedMessage(func(ctx context.Context, msg *nats.Msg) (proto.Message, error) {
+		var req messages.ChatRequest
+		if err := natsutil.Decode(msg.Data, &req); err != nil {
 			slog.Error("decode failed", "error", err)
 			return &messages.ErrorResponse{Error: true, Message: err.Error(), Type: "DecodeError"}, nil
 		}
 
-		query := req.EffectiveQuery()
-		requestID := req.RequestID
+		query := messages.EffectiveQuery(&req)
+		requestID := req.RequestId
 		if requestID == "" {
 			requestID = "unknown"
 		}
-		userID := req.UserID
+		userID := req.UserId
 		if userID == "" {
 			userID = "unknown"
 		}
-		enableRAG := req.EnableRAG
+		enableRAG := req.EnableRag
 		if !enableRAG && req.Premium {
 			enableRAG = true
 		}
@@ -71,13 +72,13 @@ func main() {
 		}
 		topK := req.TopK
 		if topK == 0 {
-			topK = ragTopK
+			topK = int32(ragTopK)
 		}
 		collection := req.Collection
 		if collection == "" {
 			collection = ragCollection
 		}
-		reqEnableTTS := req.EnableTTS || enableTTS
+		reqEnableTTS := req.EnableTts || enableTTS
 		systemPrompt := req.SystemPrompt
 		responseSubject := req.ResponseSubject
 		if responseSubject == "" {
@@ -159,18 +160,19 @@ func main() {
 
 		// 5. Generate LLM response (streaming when requested)
 		var responseText string
+		var err error
 		if req.EnableStreaming {
 			streamSubject := fmt.Sprintf("ai.chat.response.stream.%s", requestID)
 			responseText, err = llm.StreamGenerate(ctx, query, contextText, systemPrompt, func(token string) {
 				_ = h.NATS.Publish(streamSubject, &messages.ChatStreamChunk{
-					RequestID: requestID,
+					RequestId: requestID,
 					Type:      "chunk",
 					Content:   token,
 					Timestamp: messages.Timestamp(),
 				})
 			})
 			_ = h.NATS.Publish(streamSubject, &messages.ChatStreamChunk{
-				RequestID: requestID,
+				RequestId: requestID,
 				Type:      "done",
 				Done:      true,
 				Timestamp: messages.Timestamp(),
@@ -181,7 +183,7 @@ func main() {
 		if err != nil {
 			slog.Error("LLM generation failed", "error", err)
 			return &messages.ChatResponse{
-				UserID:  userID,
+				UserId:  userID,
 				Success: false,
 				Error:   err.Error(),
 			}, nil
@@ -199,15 +201,15 @@ func main() {
 		}
 
 		result := &messages.ChatResponse{
-			UserID:       userID,
+			UserId:       userID,
 			Response:     responseText,
 			ResponseText: responseText,
-			UsedRAG:      usedRAG,
+			UsedRag:      usedRAG,
 			Success:      true,
 			Audio:        audio,
 		}
 		if includeSources {
-			result.RAGSources = ragSources
+			result.RagSources = ragSources
 		}
 
 		// Publish to the response subject the frontend is waiting on