fix(github_graphql): reuse ApiClient transport for GraphQL to enable token refresh

Replace oauth2.StaticTokenSource-based HTTP client with the underlying http.Client from ApiAsyncClient.

Previously, the GraphQL client constructed its own HTTP client using StaticTokenSource, which froze the access token at task start time. This caused GitHub App installation tokens (which expire after ~1 hour) to become invalid during long-running pipelines, leading to persistent 401 errors.

Now, the GraphQL client reuses apiClient.GetClient(), which is already configured with RefreshRoundTripper and TokenProvider. This enables automatic token refresh on 401 responses, aligning GraphQL behavior with the REST client.

Design decisions:
- Reuse transport layer instead of duplicating authentication logic to ensure consistency across REST and GraphQL clients.
- Avoid StaticTokenSource, as it prevents token refresh and breaks long-running pipelines.
- Leverage existing RefreshRoundTripper for transparent token rotation without modifying GraphQL query logic.
- Keep protocol-specific logic (GraphQL vs REST) separate while sharing the underlying HTTP transport.

This ensures GraphQL pipelines using GitHub App authentication can run beyond token expiry without failure.

Fixes #8788 (bug 2)

Author: Ke-vin-S

backend/plugins/github_graphql/impl/impl.go

@@ -20,10 +20,8 @@ package impl
 import (
 	"context"
 	"fmt"
-	"net/http"
 	"net/url"
 	"reflect"
-	"strings"
 	"time"
 
 	"github.com/apache/incubator-devlake/core/models/domainlayer/devops"
@@ -39,7 +37,6 @@ import (
 	"github.com/apache/incubator-devlake/plugins/github_graphql/model/migrationscripts"
 	"github.com/apache/incubator-devlake/plugins/github_graphql/tasks"
 	"github.com/merico-ai/graphql"
-	"golang.org/x/oauth2"
 )
 
 // make sure interface is implemented
@@ -180,45 +177,18 @@ func (p GithubGraphql) PrepareTaskData(taskCtx plugin.TaskContext, options map[s
 		return nil, err
 	}
 
-	tokens := strings.Split(connection.Token, ",")
-	src := oauth2.StaticTokenSource(
-		&oauth2.Token{AccessToken: tokens[0]},
-	)
-	oauthContext := taskCtx.GetContext()
-	proxy := connection.GetProxy()
-	if proxy != "" {
-		pu, err := url.Parse(proxy)
-		if err != nil {
-			return nil, errors.Convert(err)
-		}
-		if pu.Scheme == "http" || pu.Scheme == "socks5" {
-			proxyClient := &http.Client{
-				Transport: &http.Transport{Proxy: http.ProxyURL(pu)},
-			}
-			oauthContext = context.WithValue(
-				taskCtx.GetContext(),
-				oauth2.HTTPClient,
-				proxyClient,
-			)
-			logger.Debug("Proxy set in oauthContext to %s", proxy)
-		} else {
-			return nil, errors.BadInput.New("Unsupported scheme set in proxy")
-		}
-	}
-
-	httpClient := oauth2.NewClient(oauthContext, src)
 	endpoint, err := errors.Convert01(url.Parse(connection.Endpoint))
 	if err != nil {
 		return nil, errors.BadInput.Wrap(err, fmt.Sprintf("malformed connection endpoint supplied: %s", connection.Endpoint))
 	}
-
 	// github.com and github enterprise have different graphql endpoints
 	endpoint.Path = "/graphql" // see https://docs.github.com/en/graphql/guides/forming-calls-with-graphql
 	if endpoint.Hostname() != "api.github.com" {
 		// see https://docs.github.com/en/enterprise-server@3.11/graphql/guides/forming-calls-with-graphql
 		endpoint.Path = "/api/graphql"
 	}
-	client := graphql.NewClient(endpoint.String(), httpClient)
+
+	client := graphql.NewClient(endpoint.String(), apiClient.GetClient())
 	graphqlClient, err := helper.CreateAsyncGraphqlClient(taskCtx, client, taskCtx.GetLogger(),
 		func(ctx context.Context, client *graphql.Client, logger log.Logger) (rateRemaining int, resetAt *time.Time, err errors.Error) {
 			var query GraphQueryRateLimit