Add support for integers and tool configuration in schema handling

This update introduces support for `jsonschema.Integer` types and updates the logic to handle nested items in schemas. Added a new default error log for unknown types using `slog.Error`. Also, integrated tool configuration with a `FunctionCallingConfig` when `dontRequireTool` is false.

schema/object.go

@@ -2,6 +2,7 @@ package schema
 
 import (
 	"errors"
+	"github.com/openai/openai-go"
 	"reflect"
 
 	"github.com/sashabaranov/go-openai/jsonschema"
@@ -19,6 +20,19 @@ func (o object) SchemaType() jsonschema.DataType {
 	return jsonschema.Object
 }
 
+func (o object) FunctionParameters() openai.FunctionParameters {
+	var properties = map[string]openai.FunctionParameters{}
+	for k, v := range o.fields {
+		properties[k] = v.FunctionParameters()
+	}
+
+	return openai.FunctionParameters{
+		"type":        "object",
+		"description": o.Description(),
+		"properties":  properties,
+	}
+}
+
 func (o object) Definition() jsonschema.Definition {
 	def := o.basic.Definition()
 	def.Type = jsonschema.Object