fix(ui): add tooltip fallback for truncated tree item names (#193)

Set tooltips on tree widget items so hovering reveals the full name
when text is truncated by column width. Covers all code paths:
- createNewItem() — initial item creation (columns 0, 1, 2)
- slotChangeObject() — Label and Label2 property updates
- slotNewDocument() — document item creation
- slotRelabelDocument() — document rename

Closes #193

src/Gui/Tree.cpp

@@ -3203,6 +3203,7 @@ void TreeWidget::slotNewDocument(const Gui::Document& Doc, bool isMainDoc)
     }
     item->setIcon(0, *documentPixmap);
     item->setText(0, QString::fromUtf8(Doc.getDocument()->Label.getValue()));
+    item->setToolTip(0, item->text(0));
     DocumentMap[&Doc] = item;
 }
 
@@ -3317,7 +3318,9 @@ void TreeWidget::slotRelabelDocument(const Gui::Document& Doc)
 {
     auto it = DocumentMap.find(&Doc);
     if (it != DocumentMap.end()) {
-        it->second->setText(0, QString::fromUtf8(Doc.getDocument()->Label.getValue()));
+        auto label = QString::fromUtf8(Doc.getDocument()->Label.getValue());
+        it->second->setText(0, label);
+        it->second->setToolTip(0, label);
     }
 }
 
@@ -4440,10 +4443,13 @@ bool DocumentItem::createNewItem(
     }
     assert(item->parent() == parent);
     item->setText(0, QString::fromUtf8(data->label.c_str()));
+    item->setToolTip(0, item->text(0));
     if (!data->label2.empty()) {
         item->setText(1, QString::fromUtf8(data->label2.c_str()));
+        item->setToolTip(1, item->text(1));
     }
     item->setText(2, QString::fromUtf8(data->internalName.c_str()));
+    item->setToolTip(2, item->text(2));
     if (!obj.showInTree() && !showHidden()) {
         item->setHidden(true);
     }
@@ -4975,6 +4981,7 @@ void TreeWidget::slotChangeObject(const Gui::ViewProviderDocumentObject& view, c
                 auto displayName = QString::fromUtf8(label);
                 for (auto item : data->items) {
                     item->setText(0, displayName);
+                    item->setToolTip(0, displayName);
                 }
             }
         }
@@ -4990,6 +4997,7 @@ void TreeWidget::slotChangeObject(const Gui::ViewProviderDocumentObject& view, c
                 auto displayName = QString::fromUtf8(label);
                 for (auto item : data->items) {
                     item->setText(1, displayName);
+                    item->setToolTip(1, displayName);
                 }
             }
         }