spatial hierarchy: storey elevation + Long Name column + resizable layout

- helpers/placement: port get_storey_elevation (placement Z, falling back
  to the Elevation attribute), matching ifcopenshell.util.placement.
- Add a secondary column: the storey elevation for IfcBuildingStorey,
  otherwise the LongName when filled. Elevations are right-aligned.
- Columns: Name is drag-resizable (interactive) and defaults to 20% of the
  width, Long Name stretches to fill the rest, and the eye is pinned to the
  right at a fixed width. Header shown so the divider can be grabbed.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/bonsaiviewer/modules/spatial_hierarchy/Panel.cpp

@@ -25,6 +25,7 @@
 
 #include <QHeaderView>
 #include <QMenu>
+#include <QShowEvent>
 #include <QSizePolicy>
 #include <QTreeWidget>
 #include <QTreeWidgetItem>
@@ -50,21 +51,26 @@ SpatialHierarchyPanel::SpatialHierarchyPanel(QWidget* parent)
 
     tree_ = new QTreeWidget(section);
     tree_->setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Expanding);
-    tree_->setColumnCount(2);
-    tree_->setHeaderLabels({"Spatial Item", ""});
+    tree_->setColumnCount(3);
+    tree_->setHeaderLabels({"Name", "Long Name", ""});
     tree_->setIconSize(QSize(16, 16));
     tree_->setSelectionMode(QAbstractItemView::ExtendedSelection);
     tree_->setUniformRowHeights(true);
+    // Name is drag-resizable, Long Name fills the rest, the eye is pinned to
+    // the right at a fixed width. Header stays visible so the Name/Long-Name
+    // divider can be dragged. Initial 20/80 split applied in showEvent once the
+    // real width is known.
     tree_->header()->setStretchLastSection(false);
-    tree_->header()->setSectionResizeMode(0, QHeaderView::Stretch);
-    tree_->header()->setSectionResizeMode(1, QHeaderView::Fixed);
-    tree_->header()->resizeSection(1, 28);
-    tree_->header()->hide();
+    tree_->header()->setSectionsMovable(false);
+    tree_->header()->setSectionResizeMode(0, QHeaderView::Interactive);  // name
+    tree_->header()->setSectionResizeMode(1, QHeaderView::Stretch);      // LongName / elevation
+    tree_->header()->setSectionResizeMode(2, QHeaderView::Fixed);        // visibility
+    tree_->header()->resizeSection(2, 28);
     section->addBodyWidget(tree_);
     addBodyWidget(section);
 
     connect(tree_, &QTreeWidget::itemClicked, this, [this](QTreeWidgetItem* item, int column) {
-        if (!item || column != 1) return;
+        if (!item || column != 2) return;
         emit visibilityToggleRequested(itemPath(item));
     });
 
@@ -83,6 +89,20 @@ SpatialHierarchyPanel::SpatialHierarchyPanel(QWidget* parent)
     });
 }
 
+void SpatialHierarchyPanel::showEvent(QShowEvent* event) {
+    components::Panel::showEvent(event);
+    // Default the Name column to 20% of the width once the panel has a real
+    // layout size; Long Name (stretch) takes the rest. Left interactive after,
+    // so the user's own drag persists.
+    if (!column_widths_initialized_) {
+        const int available = tree_->viewport()->width();
+        if (available > 100) {
+            tree_->header()->resizeSection(0, available / 5);
+            column_widths_initialized_ = true;
+        }
+    }
+}
+
 void SpatialHierarchyPanel::setNodes(const QList<TreeNode>& nodes) {
     tree_->clear();
     for (const auto& node : nodes) {
@@ -92,11 +112,15 @@ void SpatialHierarchyPanel::setNodes(const QList<TreeNode>& nodes) {
 }
 
 void SpatialHierarchyPanel::addNode(QTreeWidgetItem* parent, const TreeNode& node) {
-    auto* item = new QTreeWidgetItem(parent, {node.name, ""});
-    item->setData(1, Qt::UserRole, node.visible);
+    auto* item = new QTreeWidgetItem(parent, {node.name, node.detail, ""});
+    item->setData(2, Qt::UserRole, node.visible);
     item->setSizeHint(0, QSize(0, 24));
     item->setIcon(0, components::icons::makeSvgIcon(iconPath(node.kind)));
-    item->setIcon(1, components::icons::makeSvgIcon(node.visible ? ":/icons/eye.svg" : ":/icons/eye-closed.svg"));
+    // Storey elevations read as right-aligned numbers; LongNames stay left.
+    if (node.kind == ItemKind::Storey) {
+        item->setTextAlignment(1, Qt::AlignRight | Qt::AlignVCenter);
+    }
+    item->setIcon(2, components::icons::makeSvgIcon(node.visible ? ":/icons/eye.svg" : ":/icons/eye-closed.svg"));
     for (const auto& child : node.children) {
         addNode(item, child);
     }

src/bonsaiviewer/modules/spatial_hierarchy/Panel.h

@@ -27,6 +27,7 @@
 
 class QTreeWidget;
 class QTreeWidgetItem;
+class QShowEvent;
 
 namespace bonsaiviewer::modules::spatial_hierarchy {
 
@@ -40,12 +41,16 @@ public:
 signals:
     void visibilityToggleRequested(const NodePath& path);
 
+protected:
+    void showEvent(QShowEvent* event) override;
+
 private:
     void addNode(QTreeWidgetItem* parent, const TreeNode& node);
     NodePath itemPath(QTreeWidgetItem* item) const;
     QString iconPath(ItemKind kind) const;
 
     QTreeWidget* tree_ = nullptr;
+    bool column_widths_initialized_ = false;
 };
 
 } // namespace bonsaiviewer::modules::spatial_hierarchy

src/bonsaiviewer/modules/spatial_hierarchy/Types.h

@@ -36,6 +36,7 @@ enum class ItemKind {
 
 struct TreeNode {
     QString name;
+    QString detail;  // secondary column: LongName, or the elevation for storeys
     ItemKind kind = ItemKind::Space;
     bool visible = true;
     QList<TreeNode> children;

src/bonsaiviewer/modules/spatial_hierarchy/View.cpp

@@ -27,7 +27,8 @@
 #include "../../../ifcparse/file.h"
 #include "../../../ifcparse/schema.h"
 
-#include "element.h"  // helpers: get_spatial_children, get_string_attribute
+#include "element.h"    // helpers: get_spatial_children, get_string_attribute
+#include "placement.h"  // helpers: get_storey_elevation
 
 #include <QCollator>
 
@@ -79,6 +80,13 @@ TreeNode buildNode(const express::Base& element) {
     node.name = displayName(element);
     node.kind = kindOf(element);
     node.visible = true;
+    // Secondary column: the storey elevation, else the LongName when filled.
+    if (node.kind == ItemKind::Storey) {
+        node.detail = QString::number(get_storey_elevation(element));
+    } else if (auto long_name = get_string_attribute(element, "LongName");
+               long_name && !long_name->empty()) {
+        node.detail = QString::fromStdString(*long_name);
+    }
     for (const auto& child : get_spatial_children(element)) {
         node.children.append(buildNode(child));
     }