fix(moonshot): resolve 401 Unauthorized errors by trimming API keys and improving request compatibility

internal/providers/helpers.go

@@ -58,9 +58,20 @@ func MessagesToOpenAIJSON(messages []models.UnifiedMessage) ([]interface{}, erro
 			}
 		}
 
+		var finalContent interface{}
+		if len(parts) == 1 {
+			if p, ok := parts[0].(map[string]interface{}); ok && p["type"] == "text" {
+				finalContent = p["text"]
+			} else {
+				finalContent = parts
+			}
+		} else {
+			finalContent = parts
+		}
+
 		msg := map[string]interface{}{
 			"role":    m.Role,
-			"content": parts,
+			"content": finalContent,
 		}
 
 		if m.ReasoningContent != nil {