feat(wallpaper): discover runtime resource packs via Wallpapers path

desktop/base/file_operations/filter_target.cpp

@@ -69,4 +69,27 @@ QStringList filter_target(const QString& dirent_path, const QStringList& filters
     return result;
 }
 
+QStringList filter_target_recursive(const QString& dirent_path, const QStringList& filters) {
+    QStringList result;
+    QDir dir(dirent_path);
+
+    if (!dir.exists()) {
+        return result;
+    }
+
+    // Collect matching files at this level (files only, same as filter_target).
+    const QFileInfoList files = dir.entryInfoList(filters, QDir::Files | QDir::NoDotAndDotDot);
+    for (const auto& entry : files) {
+        result.append(entry.absoluteFilePath());
+    }
+
+    // Descend into each subdirectory so nested resource packs are discovered.
+    const QFileInfoList subdirs = dir.entryInfoList(QDir::Dirs | QDir::NoDotAndDotDot);
+    for (const auto& sub : subdirs) {
+        result.append(filter_target_recursive(sub.absoluteFilePath(), filters));
+    }
+
+    return result;
+}
+
 } // namespace cf::desktop::base::filesystem

desktop/base/file_operations/filter_target.h

@@ -40,4 +40,28 @@ QStringList& request_filterlist(const FilterType what);
  * @return QStringList
  */
 QStringList filter_target(const QString& dirent_path, const QStringList& filters);
+
+/**
+ * @brief  Recursively list files matching the filters under a directory.
+ *
+ * Like filter_target(), but descends into subdirectories so that files
+ * nested in pack subdirectories (for example a wallpaper resource pack
+ * installed under wallpapers/<pack>/) are discovered. The top-level
+ * directory and every subdirectory are scanned; matching file paths are
+ * accumulated.
+ *
+ * @param[in] dirent_path  Absolute path of the root directory to scan.
+ * @param[in] filters      Name filters to match (for example image globs).
+ *
+ * @return  Absolute file paths of matching files; empty if the directory
+ *          does not exist or no file matches.
+ *
+ * @throws  None.
+ *
+ * @note    None.
+ * @warning None.
+ * @since   0.19
+ * @ingroup filesystem
+ */
+QStringList filter_target_recursive(const QString& dirent_path, const QStringList& filters);
 } // namespace cf::desktop::base::filesystem

desktop/base/path/include/cfpath/desktop_main_path_resolvers.h

@@ -22,7 +22,8 @@ namespace cf::desktop::path {
  * @brief  Provider for desktop main directory paths.
  *
  * Manages resolution of standard desktop directory paths including Home,
- * Desktop, Documents, Downloads, Music, Pictures, Videos, Apps, and Runtime.
+ * Desktop, Documents, Downloads, Music, Pictures, Wallpapers, Videos, Apps,
+ * and Runtime.
  *
  * @ingroup desktop_base
  */
@@ -41,6 +42,7 @@ class DesktopMainPathProvider : public aex::Singleton<DesktopMainPathProvider> {
     X(Downloads)      \
     X(Music)          \
     X(Pictures)       \
+    X(Wallpapers)     \
     X(Videos)         \
     X(Apps)           \
     X(Runtime)

desktop/ui/components/shell_layer_impl/wallpaper_setup.cpp

@@ -1,5 +1,6 @@
 #include "wallpaper_setup.h"
 #include "cflog.h"
+#include "cfpath/desktop_main_path_resolvers.h"
 #include "filter_target.h"
 #include "shell_layer_impl/WallpaperShellLayerStrategy.h"
 #include "wallpaper/ImageWallPaperLayer.h"
@@ -19,13 +20,30 @@ std::unique_ptr<WallPaperLayer> make_layer() {
     using namespace base::filesystem;
 
     auto layer = std::make_unique<ImageWallPaperLayer>();
-    // Resolve wallpaper pictures through policy chain
+    const QStringList pic_filters = request_filterlist(FilterType::Pictures);
+
+    // Primary source: policy chain (config source_path -> Pictures), flat scan.
     auto picture_dirent = WallpaperImages().execute();
-    if (!picture_dirent.has_value() || picture_dirent->isEmpty()) {
-        return layer; // return out!
+    QStringList pictures;
+    if (picture_dirent.has_value() && !picture_dirent->isEmpty()) {
+        pictures = filter_target(picture_dirent.value(), pic_filters);
+    }
+
+    // Fallback: bundled Wallpapers directory, scanned recursively so resource
+    // packs installed under wallpapers/<pack>/ are discovered. Tried only when
+    // the primary source yielded nothing, so users with their own pictures are
+    // unaffected; an empty Pictures directory now falls through to the bundled
+    // pack instead of leaving the desktop without a wallpaper.
+    if (pictures.isEmpty()) {
+        const QString wallpapers_dir = path::DesktopMainPathProvider::instance().absolutePath(
+            path::DesktopMainPathProvider::PathType::Wallpapers);
+        pictures = filter_target_recursive(wallpapers_dir, pic_filters);
+    }
+
+    if (pictures.isEmpty()) {
+        return layer; // No wallpaper available anywhere.
     }
 
-    auto pictures = filter_target(picture_dirent.value(), request_filterlist(FilterType::Pictures));
     auto storage = std::make_unique<WallPaperAccessStorage>();
     storage->addTokens(WallPaperTokenFactory::fromFiles(pictures));
     log::tracef("Initialized with {} files", storage->size());

document/status/current.md

@@ -59,6 +59,7 @@ description: CFDesktop 项目进度的唯一事实来源与全局导航。
 ## 最近里程碑（git 可证）
 
 - **2026-06**：`refactor: refactor the ui subsystem`；`hwtier system enabled`；文档清理
+- **2026-06（壁纸资源包发现）**：壁纸层支持运行时动态发现第三方资源包——新增 `Wallpapers` PathType（`<desktop_active_root>/Wallpapers/`）+ `filter_target_recursive` 递归扫描；`make_layer()` 改为「首个有图的源胜出」（config → Pictures 平铺，空则回退 Wallpapers 递归）。CF-Gallery 等包安装到 `Wallpapers/<pack>/` 即被发现，**CFDesktop 零编译期耦合**（无 submodule/无 `#ifdef`/无 CMake option）。详见 [aels_cross_repo_deps.md](../todo/desktop/aels_cross_repo_deps.md)。动画轮播引擎（Gradient/Movement）留待下一批。
 - **已达成**：Milestone 1「桌面骨架可见」；Phase 0 / 1 / 2 / A(CI) / 6 / G(Widget) / H(显示后端)（详见 [SUMMARY.md](../todo/done/SUMMARY.md)）
 
 ## 新人入门

document/todo/desktop/aels_cross_repo_deps.md

@@ -21,6 +21,7 @@ description: CFDesktop 消费的 AELS 组织独立仓（含拟新建）的跨仓
 | **lightroot** | 现代化 BuildRoot（根文件系统构建） | 与 OTA/部署同层 |
 | **edgecv** | OpenCV 封装（desktop + embedded） | 相机/图像应用可选依赖 |
 | **bareline** | 嵌入式+PC CLI 交互框架 | 终端 App 的 pty 层可借鉴 |
+| **CF-Gallery** | 摄影静物壁纸静态资源包（CC BY-NC-ND 4.0，VitePress 收录站） | **非构建依赖**：运行时动态发现——资源包安装到 `<desktop_active_root>/Wallpapers/<pack>/`（默认 `~/desktop/Wallpapers/`）即被壁纸层递归扫描消费。CFDesktop 零编译期耦合（**无 submodule、无 `#ifdef`、无 CMake option**）；图片绝不进二进制，「开关」=是否安装了该资源包。 |
 
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