fix: correct ListOffsets v1 request parsing for kafka-go compatibility

- Fixed ListOffsets v1 to parse replica_id field (present in v1+, not v2+)
- Fixed ListOffsets v1 response format - now 55 bytes instead of 64
- kafka-go now successfully passes ListOffsets and makes Fetch requests
- Identified next issue: Fetch response format has incorrect topic count

Progress: kafka-go client now progresses to Fetch API but fails due to Fetch response format mismatch.

weed/mq/kafka/protocol/handler.go

@@ -465,6 +465,7 @@ func (h *Handler) handleApiVersions(correlationID uint32) ([]byte, error) {
 	response = append(response, 0, 0)  // min version 0
 	response = append(response, 0, 4)  // max version 4
 
+	fmt.Printf("DEBUG: ApiVersions v0 response: %d bytes\n", len(response))
 	return response, nil
 }
 
@@ -851,6 +852,7 @@ func (h *Handler) HandleMetadataV3V4(correlationID uint32, requestBody []byte) (
 	}
 
 	response := buf.Bytes()
+	fmt.Printf("DEBUG: Metadata v4 response size: %d bytes, hex: %x\n", len(response), response)
 
 	return response, nil
 }
@@ -1128,15 +1130,23 @@ func (h *Handler) handleListOffsets(correlationID uint32, apiVersion uint16, req
 	clientIDSize := binary.BigEndian.Uint16(requestBody[0:2])
 	offset := 2 + int(clientIDSize)
 
-	// ListOffsets v2+ has additional fields: replica_id(4) + isolation_level(1)
-	if apiVersion >= 2 {
-		if len(requestBody) < offset+5 {
-			return nil, fmt.Errorf("ListOffsets v%d request missing replica_id/isolation_level", apiVersion)
+	// ListOffsets v1+ has replica_id(4), v2+ adds isolation_level(1)
+	if apiVersion >= 1 {
+		if len(requestBody) < offset+4 {
+			return nil, fmt.Errorf("ListOffsets v%d request missing replica_id", apiVersion)
 		}
 		replicaID := int32(binary.BigEndian.Uint32(requestBody[offset : offset+4]))
-		isolationLevel := requestBody[offset+4]
-		offset += 5
-		fmt.Printf("DEBUG: ListOffsets v%d - replica_id: %d, isolation_level: %d\n", apiVersion, replicaID, isolationLevel)
+		offset += 4
+		fmt.Printf("DEBUG: ListOffsets v%d - replica_id: %d\n", apiVersion, replicaID)
+		
+		if apiVersion >= 2 {
+			if len(requestBody) < offset+1 {
+				return nil, fmt.Errorf("ListOffsets v%d request missing isolation_level", apiVersion)
+			}
+			isolationLevel := requestBody[offset]
+			offset += 1
+			fmt.Printf("DEBUG: ListOffsets v%d - isolation_level: %d\n", apiVersion, isolationLevel)
+		}
 	}
 
 	if len(requestBody) < offset+4 {
@@ -1256,7 +1266,7 @@ func (h *Handler) handleListOffsets(correlationID uint32, apiVersion uint16, req
 		}
 	}
 
-	fmt.Printf("DEBUG: ListOffsets v%d response: %d bytes\n", apiVersion, len(response))
+	fmt.Printf("DEBUG: ListOffsets v%d response: %d bytes, hex: %x\n", apiVersion, len(response), response)
 	return response, nil
 }