fix(executor): enhance parsing of OpenAI stream data lines

- Added trimming for stream input lines to prevent processing of unnecessary whitespace.
- Improved handling of unsupported prefixes and malformed JSON responses, ensuring errors are recorded and propagated appropriately.

Fixed: #2690

internal/runtime/executor/openai_compat_executor.go

@@ -283,17 +283,31 @@ func (e *OpenAICompatExecutor) ExecuteStream(ctx context.Context, auth *cliproxy
 			if detail, ok := helps.ParseOpenAIStreamUsage(line); ok {
 				reporter.Publish(ctx, detail)
 			}
-			if len(line) == 0 {
+			trimmedLine := bytes.TrimSpace(line)
+			if len(trimmedLine) == 0 {
 				continue
 			}
 
-			if !bytes.HasPrefix(line, []byte("data:")) {
+			if !bytes.HasPrefix(trimmedLine, []byte("data:")) {
+				if bytes.HasPrefix(trimmedLine, []byte(":")) || bytes.HasPrefix(trimmedLine, []byte("event:")) ||
+					bytes.HasPrefix(trimmedLine, []byte("id:")) || bytes.HasPrefix(trimmedLine, []byte("retry:")) {
+					continue
+				}
+				if bytes.HasPrefix(trimmedLine, []byte("{")) || bytes.HasPrefix(trimmedLine, []byte("[")) {
+					streamErr := statusErr{code: http.StatusBadGateway, msg: string(trimmedLine)}
+					helps.RecordAPIResponseError(ctx, e.cfg, streamErr)
+					reporter.PublishFailure(ctx)
+					select {
+					case out <- cliproxyexecutor.StreamChunk{Err: streamErr}:
+					case <-ctx.Done():
+					}
+					return
+				}
 				continue
 			}
 
-			// OpenAI-compatible streams are SSE: lines typically prefixed with "data: ".
-			// Pass through translator; it yields one or more chunks for the target schema.
-			chunks := sdktranslator.TranslateStream(ctx, to, from, req.Model, opts.OriginalRequest, translated, bytes.Clone(line), &param)
+			// OpenAI-compatible streams must use SSE data lines.
+			chunks := sdktranslator.TranslateStream(ctx, to, from, req.Model, opts.OriginalRequest, translated, bytes.Clone(trimmedLine), &param)
 			for i := range chunks {
 				select {
 				case out <- cliproxyexecutor.StreamChunk{Payload: chunks[i]}: