feat: move Files to its own process; add window server messaging (multi-format clipboard, drag and drop), undo/redo, sidebar, breadcrumbs, thumbnails, file type icons, New menu and proper text fields

programs/include/gui/desktop.hpp

@@ -96,6 +96,18 @@ struct DesktopSettings {
     int tz_offset_minutes;  // timezone offset from UTC in minutes
 };
 
+// The standard folders in a home directory, in display order, with their
+// icons (0:/os/icons). Shared by the desktop launcher and Files.
+inline constexpr int SPECIAL_FOLDER_COUNT = 6;
+inline constexpr const char* kSpecialFolderNames[SPECIAL_FOLDER_COUNT] = {
+    "Documents", "Desktop", "Music", "Videos", "Pictures", "Downloads"
+};
+inline constexpr const char* kSpecialFolderIcons[SPECIAL_FOLDER_COUNT] = {
+    "folder-blue-documents.svg", "folder-blue-desktop.svg",
+    "folder-blue-music.svg", "folder-blue-videos.svg",
+    "folder-blue-pictures.svg", "folder-blue-downloads.svg"
+};
+
 struct DesktopState {
     Framebuffer fb;
     Window windows[MAX_WINDOWS];
@@ -128,6 +140,55 @@ struct DesktopState {
     // releases are delivered too) so mouse handlers can see Ctrl/Shift.
     bool kbd_shift_down;
     bool kbd_ctrl_down;
+    bool kbd_alt_down;
+
+    // Drag and drop between windows (desktop/messaging.cpp). The source app
+    // starts it with SYS_WIN_DRAG_BEGIN; the desktop routes the pointer.
+    struct {
+        bool active;
+        uint32_t serial;
+        int source_ext_id;
+        uint8_t actions;          // WIN_DRAG_* offered by the source
+        uint32_t item_count;
+        char label[64];
+        int target_ext_id;        // window under the pointer, -1 = none
+        uint8_t target_action;    // last WIN_REQ_DRAG_STATUS answer
+        bool target_answered;
+        int last_x, last_y;
+        uint8_t last_modifiers;
+        bool over_desktop;        // pointer over the background, not a window
+    } drag;
+
+    // The user's Desktop folder, shown as icons on the background
+    // (desktop/desktop_icons.cpp).
+    struct DesktopIcon {
+        char name[128];
+        bool is_dir;
+    };
+    DesktopIcon* desktop_icons;
+    int desktop_icon_count;
+    int desktop_icon_cap;
+    uint64_t desktop_icons_hash;      // detects changes between rescans
+    uint64_t desktop_icons_next_scan; // ms
+    int desktop_icon_selected;        // -1 = none
+    int desktop_icon_press;           // icon the left button went down on, -1 = none
+    int desktop_icon_press_x, desktop_icon_press_y;
+    int desktop_icon_last_click;
+    uint64_t desktop_icon_last_click_ms;
+    // An incoming drag over the background: its file list (read once per
+    // serial) and the icon highlighted as the drop target.
+    uint32_t desktop_drop_serial;
+    char* desktop_drop_list;
+    int desktop_drop_icon;
+
+    // WIN_REQ_SET_PARENT requests whose dialog window has not been mapped
+    // yet; applied as soon as it appears.
+    struct {
+        int child_ext_id;
+        int parent_ext_id;
+        uint64_t expires_ms;
+    } pending_parents[8];
+    int pending_parent_count;
 
     SvgIcon icon_terminal;
     SvgIcon icon_filemanager;
@@ -168,7 +229,7 @@ struct DesktopState {
     SvgIcon icon_system_configuration_lg;
 
     // Special user folder icons (16x16 and 48x48)
-    static constexpr int SPECIAL_FOLDER_COUNT = 6;
+    static constexpr int SPECIAL_FOLDER_COUNT = gui::SPECIAL_FOLDER_COUNT;
     SvgIcon icon_special_folder[SPECIAL_FOLDER_COUNT];
     SvgIcon icon_special_folder_lg[SPECIAL_FOLDER_COUNT];