Fix kafka-go compatibility:

- ApiVersions v0 response: remove unsupported throttle_time field
- Metadata v1: include correlation ID (kafka-go transport expects it after size)
- Metadata v1: ensure broker/partition IDs consistent and format correct

Validated:
- TestMetadataV6Debug passes (kafka-go ReadPartitions works)
- Sarama simple producer unaffected

Root cause: correlation ID handling differences and extra footer in ApiVersions.

weed/mq/kafka/protocol/handler.go

@@ -308,7 +308,7 @@ func (h *Handler) HandleConn(conn net.Conn) error {
 
 func (h *Handler) handleApiVersions(correlationID uint32) ([]byte, error) {
 	// Build ApiVersions response manually
-	// Response format: correlation_id(4) + error_code(2) + num_api_keys(4) + api_keys + throttle_time(4)
+	// Response format (v0): correlation_id(4) + error_code(2) + num_api_keys(4) + api_keys
 
 	response := make([]byte, 0, 64)
 
@@ -396,9 +396,6 @@ func (h *Handler) handleApiVersions(correlationID uint32) ([]byte, error) {
 	response = append(response, 0, 0)  // min version 0
 	response = append(response, 0, 4)  // max version 4
 
-	// Throttle time (4 bytes, 0 = no throttling)
-	response = append(response, 0, 0, 0, 0)
-
 	return response, nil
 }
 
@@ -531,8 +528,10 @@ func (h *Handler) HandleMetadataV1(correlationID uint32, requestBody []byte) ([]
 	// Build response using same approach as v0 but with v1 additions
 	response := make([]byte, 0, 256)
 
-	// NOTE: Correlation ID is handled by transport layer in kafka-go
-	// Do NOT include it in the response struct
+	// Correlation ID (4 bytes)
+	correlationIDBytes := make([]byte, 4)
+	binary.BigEndian.PutUint32(correlationIDBytes, correlationID)
+	response = append(response, correlationIDBytes...)
 
 	// Brokers array length (4 bytes) - 1 broker (this gateway)
 	response = append(response, 0, 0, 0, 1)