Fix unmarshalling issues and adjust logging for debugging

Modify `FunctionCall` struct to handle arguments as strings. Add debugging logs to facilitate error tracing and improve JSON unmarshalling in various functions.

google.go

@@ -2,6 +2,7 @@ package go_llm
 
 import (
 	"context"
+	"encoding/json"
 	"fmt"
 	"github.com/google/generative-ai-go/genai"
 	"google.golang.org/api/option"
@@ -63,11 +64,17 @@ func (g google) responseToLLMResponse(in *genai.GenerateContentResponse) (Respon
 					choice := ResponseChoice{}
 
 					choice.Content = v.Name
+					b, e := json.Marshal(v.Args)
+
+					if e != nil {
+						return Response{}, fmt.Errorf("error marshalling args: %w", e)
+					}
+
 					call := ToolCall{
 						ID: v.Name,
 						FunctionCall: FunctionCall{
 							Name:      v.Name,
-							Arguments: v.Args,
+							Arguments: string(b),
 						},
 					}