refactor: streamline ConvertCodexResponseToGeminiNonStream by removing unnecessary buffer and improving response handling

internal/translator/codex/gemini/codex_gemini_response.go

@@ -5,7 +5,6 @@
 package gemini
 
 import (
-	"bufio"
 	"bytes"
 	"context"
 	"encoding/json"
@@ -152,22 +151,11 @@ func ConvertCodexResponseToGemini(_ context.Context, modelName string, originalR
 // Returns:
 //   - string: A Gemini-compatible JSON response containing all message content and metadata
 func ConvertCodexResponseToGeminiNonStream(_ context.Context, modelName string, originalRequestRawJSON, requestRawJSON, rawJSON []byte, _ *any) string {
-	scanner := bufio.NewScanner(bytes.NewReader(rawJSON))
-	buffer := make([]byte, 20_971_520)
-	scanner.Buffer(buffer, 20_971_520)
-	for scanner.Scan() {
-		line := scanner.Bytes()
-		// log.Debug(string(line))
-		if !bytes.HasPrefix(line, dataTag) {
-			continue
-		}
-		rawJSON = bytes.TrimSpace(rawJSON[5:])
-
 	rootResult := gjson.ParseBytes(rawJSON)
 
 	// Verify this is a response.completed event
 	if rootResult.Get("type").String() != "response.completed" {
-			continue
+		return ""
 	}
 
 	// Base Gemini response template for non-streaming
@@ -303,8 +291,6 @@ func ConvertCodexResponseToGeminiNonStream(_ context.Context, modelName string,
 		}
 	}
 	return template
-	}
-	return ""
 }
 
 // buildReverseMapFromGeminiOriginal builds a map[short]original from original Gemini request tools.