[CHA-2354] Add ParsedPredefinedFilterResponse to QueryChannels response

Add struct and response field for the new `predefined_filter` property
returned in QueryChannels responses when a predefined filter is used.

- Added ParsedPredefinedFilterResponse struct
- Updated queryChannelResponse and QueryChannelsResponse
- Added unit tests for JSON unmarshaling

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: totalimmersion

query.go

@@ -94,8 +94,17 @@ func (c *Client) QueryUsers(ctx context.Context, q *QueryUsersOptions, sorters .
 	return &resp, err
 }
 
+// ParsedPredefinedFilterResponse contains the interpolated filter and sort from a predefined filter.
+// This is returned in the QueryChannels response when using a predefined filter.
+type ParsedPredefinedFilterResponse struct {
+	Name   string                 `json:"name"`
+	Filter map[string]interface{} `json:"filter"`
+	Sort   []*SortOption          `json:"sort,omitempty"`
+}
+
 type queryChannelResponse struct {
-	Channels []queryChannelResponseData `json:"channels"`
+	Channels         []queryChannelResponseData      `json:"channels"`
+	PredefinedFilter *ParsedPredefinedFilterResponse `json:"predefined_filter,omitempty"`
 	Response
 }
 
@@ -113,7 +122,8 @@ type queryChannelResponseData struct {
 }
 
 type QueryChannelsResponse struct {
-	Channels []*Channel
+	Channels         []*Channel
+	PredefinedFilter *ParsedPredefinedFilterResponse
 	Response
 }
 
@@ -157,7 +167,11 @@ func (c *Client) QueryChannels(ctx context.Context, q *QueryOption, sort ...*Sor
 		result[i].client = c
 	}
 
-	return &QueryChannelsResponse{Channels: result, Response: resp.Response}, nil
+	return &QueryChannelsResponse{
+		Channels:         result,
+		PredefinedFilter: resp.PredefinedFilter,
+		Response:         resp.Response,
+	}, nil
 }
 
 type SearchRequest struct {

query_test.go

@@ -2,6 +2,7 @@ package stream_chat
 
 import (
 	"context"
+	"encoding/json"
 	"fmt"
 	"testing"
 	"time"
@@ -320,6 +321,45 @@ func TestClient_QueryMessageFlags(t *testing.T) {
 	assert.Len(t, got.Flags, 1)
 }
 
+func TestQueryChannelsResponse_ParsedPredefinedFilter(t *testing.T) {
+	// Test that ParsedPredefinedFilterResponse is correctly unmarshaled from JSON
+	jsonData := `{
+		"channels": [],
+		"predefined_filter": {
+			"name": "user_messaging",
+			"filter": {"type": "messaging", "members": {"$in": ["user123"]}},
+			"sort": [{"field": "last_message_at", "direction": -1}]
+		},
+		"duration": "0.01s"
+	}`
+
+	var resp queryChannelResponse
+	err := json.Unmarshal([]byte(jsonData), &resp)
+	require.NoError(t, err)
+
+	require.NotNil(t, resp.PredefinedFilter)
+	require.Equal(t, "user_messaging", resp.PredefinedFilter.Name)
+	require.NotNil(t, resp.PredefinedFilter.Filter)
+	require.Equal(t, "messaging", resp.PredefinedFilter.Filter["type"])
+	require.Len(t, resp.PredefinedFilter.Sort, 1)
+	require.Equal(t, "last_message_at", resp.PredefinedFilter.Sort[0].Field)
+	require.Equal(t, -1, resp.PredefinedFilter.Sort[0].Direction)
+}
+
+func TestQueryChannelsResponse_NoPredefinedFilter(t *testing.T) {
+	// Test that response without predefined_filter has nil PredefinedFilter
+	jsonData := `{
+		"channels": [],
+		"duration": "0.01s"
+	}`
+
+	var resp queryChannelResponse
+	err := json.Unmarshal([]byte(jsonData), &resp)
+	require.NoError(t, err)
+
+	require.Nil(t, resp.PredefinedFilter)
+}
+
 func TestClient_QueryFlagReportsAndReview(t *testing.T) {
 	c := initClient(t)
 	ch := initChannel(t, c)