fix: allow xdg activation without window information

Remove the early return when no target window is available for XDG
activation tokens. Previously, the token request would fail immediately
if there was no effective window, but tray plugins might need to use XDG
activation without a window context.

Log: XDG activation now works without requiring a window

Influence:
1. Test tray icon activation without a focused window
2. Verify token generation succeeds with null/empty window
3. Ensure no regression when window context is provided
4. Test activation request flow in headless or windowless scenarios

fix: 允许无窗口信息时进行XDG激活

移除当没有目标窗口时提前返回XDG激活令牌的逻辑。之前没有有效窗口时令牌请
求会立即失败，但托盘插件可能需要在没有窗口上下文的情况下使用XDG激活。

Log: XDG激活现在无需窗口即可工作

Influence:
1. 测试无焦点窗口时的托盘图标激活功能
2. 验证在窗口为空/null时令牌生成是否成功
3. 确保有窗口上下文时功能正常无回归
4. 测试无窗口或headless场景下的激活请求流程

Author: 18202781743

src/tray-wayland-integration/xdgactivation.cpp

@@ -144,11 +144,6 @@ void XdgActivation::requestToken(QWindow *window, const QString &appId)
         qCWarning(trayXdgActivation) << "XDG activation request has empty app id";
 
     auto effectiveWindow = window ? window : QGuiApplication::focusWindow();
-    if (!effectiveWindow) {
-        qCWarning(trayXdgActivation) << "XDG activation request has no target window";
-        Q_EMIT tokenReady({});
-        return;
-    }
 
     auto *provider = activationV1()->createTokenProvider(effectiveWindow, effectiveAppId);
     provider->setParent(this);