revert: completely remove all Sora functionality

backend/internal/service/openai_oauth_service_auth_url_test.go

@@ -43,25 +43,3 @@ func TestOpenAIOAuthService_GenerateAuthURL_OpenAIKeepsCodexFlow(t *testing.T) {
 	require.True(t, ok)
 	require.Equal(t, openai.ClientID, session.ClientID)
 }
-
-// TestOpenAIOAuthService_GenerateAuthURL_SoraUsesCodexClient 验证 Sora 平台复用 Codex CLI 的
-// client_id（支持 localhost redirect_uri），但不启用 codex_cli_simplified_flow。
-func TestOpenAIOAuthService_GenerateAuthURL_SoraUsesCodexClient(t *testing.T) {
-	svc := NewOpenAIOAuthService(nil, &openaiOAuthClientAuthURLStub{})
-	defer svc.Stop()
-
-	result, err := svc.GenerateAuthURL(context.Background(), nil, "", PlatformSora)
-	require.NoError(t, err)
-	require.NotEmpty(t, result.AuthURL)
-	require.NotEmpty(t, result.SessionID)
-
-	parsed, err := url.Parse(result.AuthURL)
-	require.NoError(t, err)
-	q := parsed.Query()
-	require.Equal(t, openai.ClientID, q.Get("client_id"))
-	require.Empty(t, q.Get("codex_cli_simplified_flow"))
-
-	session, ok := svc.sessionStore.Get(result.SessionID)
-	require.True(t, ok)
-	require.Equal(t, openai.ClientID, session.ClientID)
-}