refactor: C++ 后端文件移入 src/ 目录，优化项目结构层级

AGENTS.md

@@ -68,8 +68,9 @@ then restart `dde-shell` (it discovers applets by scanning the install dir for
 ├── CMakeLists.txt                 # Build configuration
 ├── install.sh                     # Install script
 ├── build-deb.sh                   # Deb packaging script
-├── networkmonitorapplet.h         # C++ backend header
-├── networkmonitorapplet.cpp       # C++ backend implementation
+├── src/
+│   ├── networkmonitorapplet.h     # C++ backend header
+│   └── networkmonitorapplet.cpp   # C++ backend implementation
 ├── package/
 │   ├── metadata.json.in           # Plugin metadata 模板（由 CMake 生成 metadata.json）
 │   └── networkview.qml            # QML UI

CMakeLists.txt

@@ -14,14 +14,15 @@ find_package(DDEShell REQUIRED)
 set(PLUGIN_ID "space.jokul.JNetApplet")
 
 add_library(space.jokul.JNetApplet SHARED
-    networkmonitorapplet.h
-    networkmonitorapplet.cpp
+    src/networkmonitorapplet.h
+    src/networkmonitorapplet.cpp
 )
 
 set_target_properties(space.jokul.JNetApplet PROPERTIES PREFIX "")
 
+# 头文件搜索路径指向 src/，使 #include "networkmonitorapplet.h" 可被外部解析
 target_include_directories(space.jokul.JNetApplet PRIVATE
-    ${CMAKE_CURRENT_SOURCE_DIR}
+    ${CMAKE_CURRENT_SOURCE_DIR}/src
     /usr/include/dde-shell
 )
 

README.md

@@ -65,8 +65,9 @@ bash build-deb.sh
 ├── CMakeLists.txt                          # 构建配置
 ├── install.sh                              # 安装脚本
 ├── build-deb.sh                            # deb 一键打包脚本
-├── networkmonitorapplet.h                  # C++ 后端头文件
-├── networkmonitorapplet.cpp                # C++ 后端实现
+├── src/
+│   ├── networkmonitorapplet.h              # C++ 后端头文件
+│   └── networkmonitorapplet.cpp            # C++ 后端实现
 ├── package/
 │   ├── metadata.json.in                   # 插件元数据模板（由 CMake 生成 metadata.json）
 │   └── networkview.qml                     # QML 界面