Route bonsai through wgpu; delete the GL backend

Bonsai now drives the wgpu viewport for both sidecar and direct-IFC
loads. The GL viewer and its supporting state classes are gone.

SceneLoader rewire:
- Takes WgpuViewportWindow* instead of ViewportWindow*.
- Sidecar path reads metadata only (readSidecarMetadataOnly) and hands
  the StreamingSidecar off to the new applyCachedModel. Field accesses
  inside applySidecarData go through .meta.
- Direct-IFC path uses the wgpu A-path (upload{Mesh,Instance}Chunk +
  finalizeModel). The applyLodExtension call is dropped — wgpu has no
  live LOD1 splice; LOD1 still lands in the on-disk sidecar for the
  next open.

Bonsai migration:
- ViewportWindow → WgpuViewportWindow across MainWindow, Measurement,
  SessionState, and every modules/*/{Commands,Panel,View}.{h,cpp} —
  116 sites total. Same s/OverlayRenderer::/WgpuOverlayRenderer::/
  rename, 12 sites.
- Includes flipped from ../ifcviewer/ViewportWindow.h to
  ../ifcviewer-wgpu/WgpuViewportWindow.h. OverlayRenderer.h include
  dropped (transitively reached via the viewport header).
- BonsaiViewer links IfcViewerWgpu in addition to IfcViewer for the
  duration of the migration; the GL-side IfcViewer also publicly links
  IfcViewerWgpu so SceneLoader can resolve WgpuViewportWindow.

GL backend deletion:
- src/ifcviewer/ViewportWindow.{cpp,h}, BvhAccel.*, OverlayRenderer.*,
  Selection.*, Visibility.* all gone.
- src/ifcviewer-minimal/ removed entirely (MinimalWindow drove the GL
  viewport).
- src/ifcviewer/tests: test_bvh_accel, test_selection, test_visibility
  removed. The first has no replacement (wgpu doesn't use a per-instance
  BVH); the latter two are ported separately. test_lod_builder,
  test_sidecar_cache, test_instanced_geometry, test_federation remain
  (backend-agnostic).
- IfcViewer's CMakeLists drops OpenGL, Qt::OpenGL, Qt::Widgets — none
  of the surviving translation units reach for them.

Build flag plumbing:
- BUILD_BONSAIVIEWER now auto-enables BUILD_BONSAIVIEWER_WGPU since
  SceneLoader requires the wgpu lib for its WgpuViewportWindow* arg.
- The wgpu subprojects add_subdirectory ahead of the GL one so
  IfcViewerWgpu exists when IfcViewer's link evaluates.
- src/ifcviewer-minimal subdir reference removed from cmake/CMakeLists.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

src/bonsaiviewer/modules/project/Commands.cpp

@@ -30,7 +30,7 @@
 #include "../models/Commands.h"
 #include "../../../ifcviewer/Federation.h"
 #include "../../../ifcviewer/SceneLoader.h"
-#include "../../../ifcviewer/ViewportWindow.h"
+#include "../../../ifcviewer-wgpu/WgpuViewportWindow.h"
 
 #include <QDebug>
 #include <QDir>
@@ -53,7 +53,7 @@ namespace {
 // Pure helper — clears the loaded scene without emitting any signals. The
 // caller (newProject / openProject) emits projectReset / projectOpened once
 // the whole flow finishes.
-void clearScene(SessionState& s, ViewportWindow& vp) {
+void clearScene(SessionState& s, WgpuViewportWindow& vp) {
     vp.setSelectedObjectId(0);
     s.setSelectedObjectId(0);
     for (uint32_t mid : s.modelIds()) {
@@ -88,7 +88,7 @@ bool confirmDiscardIfDirty(SessionState& s, QWidget& host) {
 //   - if no scene entry exists yet (initial open), queue a load.
 // Per spec, connector errors are not surfaced to the user; the connector
 // has already shown its own UI.
-void resolveCloudModels(SessionState& s, ViewportWindow& vp) {
+void resolveCloudModels(SessionState& s, WgpuViewportWindow& vp) {
     auto* fed = s.federation();
     QHash<QString, QStringList> connector_to_fed_ids;
     for (const auto& m : fed->models()) {
@@ -99,7 +99,7 @@ void resolveCloudModels(SessionState& s, ViewportWindow& vp) {
 
     auto* registry = s.connectorRegistry();
     QPointer<SessionState> sguard(&s);
-    QPointer<ViewportWindow> vguard(&vp);
+    QPointer<WgpuViewportWindow> vguard(&vp);
 
     for (auto it = connector_to_fed_ids.constBegin();
               it != connector_to_fed_ids.constEnd(); ++it) {
@@ -203,7 +203,7 @@ bool isIfcfedUnchanged(const QString& current_path, const QString& candidate_pat
     return a.readAll() == b.readAll();
 }
 
-bool openProjectAt(SessionState& s, QWidget& host, ViewportWindow& vp, const QString& path) {
+bool openProjectAt(SessionState& s, QWidget& host, WgpuViewportWindow& vp, const QString& path) {
     SceneLoader* loader = s.loader();
     if (loader && loader->isLoading()) {
         QMessageBox::information(
@@ -268,7 +268,7 @@ bool saveProjectTo(SessionState& s, QWidget& host, const QString& path) {
 
 } // namespace
 
-bool newProject(SessionState& s, QWidget& host, ViewportWindow& vp) {
+bool newProject(SessionState& s, QWidget& host, WgpuViewportWindow& vp) {
     SceneLoader* loader = s.loader();
     if (loader && loader->isLoading()) {
         QMessageBox::information(
@@ -285,7 +285,7 @@ bool newProject(SessionState& s, QWidget& host, ViewportWindow& vp) {
     return true;
 }
 
-bool openProject(SessionState& s, QWidget& host, ViewportWindow& vp) {
+bool openProject(SessionState& s, QWidget& host, WgpuViewportWindow& vp) {
     QFileDialog file_dialog(&host, "Open Project");
     file_dialog.setFileMode(QFileDialog::ExistingFile);
     file_dialog.setNameFilter("IFC Federation (*.ifcfed);;All Files (*)");
@@ -297,12 +297,12 @@ bool openProject(SessionState& s, QWidget& host, ViewportWindow& vp) {
     return openProjectAt(s, host, vp, path);
 }
 
-bool openProjectPath(SessionState& s, QWidget& host, ViewportWindow& vp, const QString& path) {
+bool openProjectPath(SessionState& s, QWidget& host, WgpuViewportWindow& vp, const QString& path) {
     if (path.isEmpty()) return false;
     return openProjectAt(s, host, vp, path);
 }
 
-bool openCloudProject(SessionState& s, QWidget& host, ViewportWindow& vp) {
+bool openCloudProject(SessionState& s, QWidget& host, WgpuViewportWindow& vp) {
     SceneLoader* loader = s.loader();
     if (loader && loader->isLoading()) {
         QMessageBox::information(
@@ -341,7 +341,7 @@ bool openCloudProject(SessionState& s, QWidget& host, ViewportWindow& vp) {
 
     QPointer<SessionState> sguard(&s);
     QPointer<QWidget> hguard(&host);
-    QPointer<ViewportWindow> vguard(&vp);
+    QPointer<WgpuViewportWindow> vguard(&vp);
 
     proc->call("pull_ifcfed_interactive", QJsonValue(),
         [sguard, hguard, vguard, connector_id](const QJsonValue& result) {
@@ -371,7 +371,7 @@ bool openCloudProject(SessionState& s, QWidget& host, ViewportWindow& vp) {
     return true;
 }
 
-bool syncCloudProject(SessionState& s, QWidget& host, ViewportWindow& vp) {
+bool syncCloudProject(SessionState& s, QWidget& host, WgpuViewportWindow& vp) {
     auto* fed = s.federation();
 
     // Per spec, sync has two independent phases — refreshing the .ifcfed
@@ -429,7 +429,7 @@ bool syncCloudProject(SessionState& s, QWidget& host, ViewportWindow& vp) {
 
     QPointer<SessionState> sguard(&s);
     QPointer<QWidget> hguard(&host);
-    QPointer<ViewportWindow> vguard(&vp);
+    QPointer<WgpuViewportWindow> vguard(&vp);
     const QString current_path = fed->filePath();
 
     proc->call("pull_ifcfed", fed->manifest(),

src/bonsaiviewer/modules/project/Commands.h

@@ -24,7 +24,7 @@
 #include <QString>
 
 class QWidget;
-class ViewportWindow;
+class WgpuViewportWindow;
 namespace bonsaiviewer { class SessionState; }
 
 namespace bonsaiviewer::modules::project::commands {
@@ -32,21 +32,21 @@ namespace bonsaiviewer::modules::project::commands {
 // User-facing commands. Each owns its own dialogs and confirmations; each
 // emits exactly one notify() at the end (projectReset / projectOpened /
 // projectSaved) so views refresh once per command.
-bool newProject(SessionState& s, QWidget& host, ViewportWindow& vp);
-bool openProject(SessionState& s, QWidget& host, ViewportWindow& vp);
+bool newProject(SessionState& s, QWidget& host, WgpuViewportWindow& vp);
+bool openProject(SessionState& s, QWidget& host, WgpuViewportWindow& vp);
 // Open a specific .ifcfed by path, bypassing the file dialog. Used by the
 // "Open Recent" menu. Same dirty-check / load / cloud-resolve flow as
 // openProject; returns false if the load failed or was cancelled.
-bool openProjectPath(SessionState& s, QWidget& host, ViewportWindow& vp, const QString& path);
+bool openProjectPath(SessionState& s, QWidget& host, WgpuViewportWindow& vp, const QString& path);
 // Pick a connector, then call pull_ifcfed_interactive and open the resulting
 // .ifcfed as a fresh project. Non-local models in the loaded federation are
 // resolved asynchronously via pull_models.
-bool openCloudProject(SessionState& s, QWidget& host, ViewportWindow& vp);
+bool openCloudProject(SessionState& s, QWidget& host, WgpuViewportWindow& vp);
 // pull_ifcfed using the current project's .ifcfed.manifest. Re-downloads
 // the .ifcfed from the same cloud target it came from (typically without
 // user interaction), then opens it like a fresh project — discarding any
 // local edits after the usual dirty-check prompt.
-bool syncCloudProject(SessionState& s, QWidget& host, ViewportWindow& vp);
+bool syncCloudProject(SessionState& s, QWidget& host, WgpuViewportWindow& vp);
 bool saveProject(SessionState& s, QWidget& host);
 bool saveProjectAs(SessionState& s, QWidget& host);
 // Push the current federation to the cloud target named in its manifest