feat: expand Files features; add file associations

programs/include/gui/desktop.hpp

@@ -46,6 +46,9 @@ struct DesktopItem {
     bool menu_visible;
     bool launch_with_home;
     bool admin_only;
+    // File extensions the app opens (manifest files.types): lowercase, no dot,
+    // space-separated with a leading and trailing space, e.g. " jpg jpeg ".
+    char file_types[160];
 };
 
 enum LauncherItemKind : uint8_t {
@@ -121,6 +124,10 @@ struct DesktopState {
     int launcher_scroll;
     bool super_left_down;
     bool super_right_down;
+    // Live modifier state, tracked from every key event (modifier presses and
+    // releases are delivered too) so mouse handlers can see Ctrl/Shift.
+    bool kbd_shift_down;
+    bool kbd_ctrl_down;
 
     SvgIcon icon_terminal;
     SvgIcon icon_filemanager;