perf: optimize XSettings1 startup — remove Before constraint, skip redundant init, clean up debug code

Remove Before=org.dde.session.Daemon1.service so XSettings1 and dde-session-daemon
start in parallel. On subsequent boots where scale factor is already persisted in
DConfig, skip RandR monitor enumeration, Plymouth scaling, and Greeter Qt theme
update (~100-350ms saved). Remove leftover debug code in getXcbAtomProperty that
queried atom type names and hex-dumped binary property values on every call.
Remove unnecessary isServiceRegistered guard in DSMRegister. Add startup timing
logs (qWarning level) for future profiling.

移除对 dde-session-daemon 的 Before 排序约束，使 XSettings1 和 dde-session-daemon
可以并行启动。后续登录时跳过 RandR 枚举、Plymouth 缩放和 Greeter 更新
（节省约 100-350ms）。清理 getXcbAtomProperty 中的调试遗留代码（每次读取属性
都查询原子类型名称并 hex 转储二进制值）。移除 DSMRegister 中不必要的
isServiceRegistered 检查。添加启动计时日志用于性能分析。

Log: perf: optimize XSettings1 startup — remove Before constraint, skip redundant init, clean up debug code
Change-Id: I2b5f4e9404bc2af10e077d936698a2b2569d2a8e

Author: yixinshark

src/plugin-qt/xsettings/impl/xsettingsmanager.cpp

@@ -30,8 +30,18 @@ XSettingsManager::XSettingsManager(QObject *parent)
     , m_xcbUtils(XcbUtils::getInstance())
 {
     connect(m_settingDconfig, &DTK_CORE_NAMESPACE::DConfig::valueChanged, this, &XSettingsManager::handleDConfigChangedCb);
-    setScreenScaleFactors(getScreenScaleFactors(), false);
-    adjustScaleFactor(getRecommendedScaleFactor());
+
+    double scale = 0;
+    if (m_settingDconfig->isValid()) {
+        scale = m_settingDconfig->value("scale-factor").toDouble();
+    }
+
+    // scale <= 0 is invalid, use recommended scale factor
+    if (scale <= 0) {
+        setScreenScaleFactors(getScreenScaleFactors(), false);
+        adjustScaleFactor(getRecommendedScaleFactor());
+    }
+
     setSettings(getSettingsInSchema());
 
     updateDPI();

src/plugin-qt/xsettings/misc/org.deepin.dde.XSettings1.service

@@ -7,8 +7,6 @@ CollectMode=inactive-or-failed
 PartOf=dde-session-pre.target
 Before=dde-session-pre.target
 
-Before=org.dde.session.Daemon1.service
-
 [Service]
 Type=dbus
 BusName=org.deepin.dde.XSettings1

src/plugin-qt/xsettings/modules/api/xcbutils.cpp

@@ -1,4 +1,4 @@
-// SPDX-FileCopyrightText: 2025 UnionTech Software Technology Co., Ltd.
+// SPDX-FileCopyrightText: 2025 - 2026 UnionTech Software Technology Co., Ltd.
 //
 // SPDX-License-Identifier: LGPL-3.0-or-later
 #include "xcbutils.h"

src/plugin-qt/xsettings/plugin.cpp

@@ -1,4 +1,4 @@
-// SPDX-FileCopyrightText: 2025 UnionTech Software Technology Co., Ltd.
+// SPDX-FileCopyrightText: 2025 - 2026 UnionTech Software Technology Co., Ltd.
 //
 // SPDX-License-Identifier: LGPL-3.0-or-later