Fix #1117: element icon vanishes from the collection after saving

Saving an element from the element editor calls
ElementsCollectionWidget::locationWasSaved(), which runs clearData() on
the panel item: the icon is set to a null QIcon. The icon only comes
back through FileElementCollectionItem::setUpIcon(), but since the
#633 recursion guard that returns for good once m_icon_initialized is
set, and nothing ever reset it. The row stayed without an icon until
the whole collection was reloaded.

#1008 refreshed the picture caches on save, but no one asked them for
the new picture, so it could not fix this. Resetting the flag in
clearData() lets the next paint rebuild the icon, which then comes
from those refreshed caches, so the panel shows the new drawing.

The flag is reset after the base clearData(): its setIcon() emits
dataChanged(), which re-enters setUpIcon() and must still return early.
setUpIcon() sets the flag before its own setIcon(), so the #633 guard
is unchanged.

The same reset should also bring back a folder's icon after editing its
properties (editDirectory() calls clearData() too); read, not tested.
Project collection items were never affected: their setUpIcon() guards
on icon().isNull().

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

sources/ElementsCollection/fileelementcollectionitem.cpp

@@ -480,6 +480,22 @@ void FileElementCollectionItem::setUpIcon()
 	}
 }
 
+/**
+	@brief FileElementCollectionItem::clearData
+	Reset the data, and let setUpIcon() build the icon again.
+	Without this the guard in setUpIcon() keeps the icon cleared here
+	empty until the whole collection is reloaded, e.g. after an element
+	is saved from the element editor (see locationWasSaved()).
+*/
+void FileElementCollectionItem::clearData()
+{
+		// Reset the flag only after the base class has cleared the icon:
+		// its setIcon() emits dataChanged(), which re-enters setUpIcon(),
+		// and that call must still see the flag set and return early.
+	ElementCollectionItem::clearData();
+	m_icon_initialized = false;
+}
+
 /**
 	@brief FileElementCollectionItem::setPathName
 	Set the name of this item in the file system path.

sources/ElementsCollection/fileelementcollectionitem.h

@@ -55,6 +55,7 @@ class FileElementCollectionItem : public ElementCollectionItem
 
 		void setUpData() override;
 		void setUpIcon() override;
+		void clearData() override;
 
 	private:
 		void setPathName(const QString& path_name,