fix(watch): fix path format and add watch for newly created directories

Ensure directories exist before adding watches and fix path format
consistency to match getDesktopFileDirs(). Dynamically add watch for
newly created application directories.

修复目录路径格式问题，并在添加监听前确保目录存在。为动态创建的应用目录添加监听。

Log: 修复目录监听问题
PMS: BUG-340395
Influence: 修复了路径格式不一致导致的目录监听失败问题，确保新创建的应用目录能被正确监听，避免应用更新后无法及时刷新。

Author: re2zero

src/dbus/applicationmanager1service.cpp

@@ -87,7 +87,21 @@ void ApplicationManager1Service::initService(QDBusConnection &connection) noexce
     }
 
     connect(&m_watcher, &QFileSystemWatcher::directoryChanged, this, &ApplicationManager1Service::ReloadApplications);
-    auto unhandled = m_watcher.addPaths(getDesktopFileDirs());
+
+    // Ensure all directories exist before adding watches
+    auto desktopDirs = getDesktopFileDirs();
+    for (const auto &dirPath : std::as_const(desktopDirs)) {
+        QDir dir(dirPath);
+        if (!dir.exists()) {
+            if (dir.mkpath(dirPath)) {
+                qInfo() << "Created directory for watching:" << dirPath;
+            } else {
+                qWarning() << "Failed to create directory:" << dirPath;
+            }
+        }
+    }
+
+    auto unhandled = m_watcher.addPaths(desktopDirs);
     for (const auto &dir : std::as_const(unhandled)) {
         qCritical() << "couldn't watch directory:" << dir;
     }
@@ -682,12 +696,27 @@ QString ApplicationManager1Service::addUserApplication(const QVariantMap &deskto
     }
 
     QDir xdgDataHome;
-    QString dir{getXDGDataHome() + "/applications"};
+    QString dir{getXDGDataHome()};
+    // Ensure consistent path format (with trailing separator) to match getDesktopFileDirs()
+    if (!dir.endsWith(QDir::separator())) {
+        dir.append(QDir::separator());
+    }
+    dir.append("applications");
+    const bool dirExisted = QDir(dir).exists();
     if (!xdgDataHome.mkpath(dir)) {
         safe_sendErrorReply(QDBusError::Failed, "couldn't create directory of user applications.");
         return {};
     }
 
+    // If directory is newly created, add watch for it dynamically
+    if (!dirExisted && !m_watcher.directories().contains(dir)) {
+        if (!m_watcher.addPath(dir)) {
+            qWarning() << "Failed to add watch for newly created directory:" << dir;
+        } else {
+            qInfo() << "Added watch for newly created directory:" << dir;
+        }
+    }
+
     // 判断当前是否已经存在了desktop文件
     xdgDataHome.setPath(dir);
     const auto &filePath = xdgDataHome.filePath(name);