Bundled builds: ship Qt WebEngine (helper process, resources)

When a bundled library is Qt WebEngine, the bundler also installs
QtWebEngineProcess (plus its libraries) to libexec/, the resources and
the en-US/de locales, and points qt.conf at them. The cross image unpacks
the arm64 QtWebEngineProcess (its package can't be co-installed with the
amd64 one). Experiment for DSH-1: the Frame's system WebEngine (6.7.0,
built against FFmpeg 6) can't be loaded.

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

cmake/BundleQt.cmake

@@ -30,6 +30,14 @@ set(VRDASH_BUNDLE_PLUGINS
     wayland-shell-integration/*.so wayland-graphics-integration-client/*.so
     wayland-decoration-client/*.so xcbglintegrations/*.so)
 
+# Qt WebEngine (bundled only if a dashboard needs it): its helper process, resources and
+# locales. Cross builds point VRDASH_WEBENGINE_PROCESS at the target's QtWebEngineProcess
+# (Debian can't install the arm64 one next to the host's; see docker/cross-arm64.Dockerfile).
+set(VRDASH_WEBENGINE_PROCESS "" CACHE FILEPATH
+    "QtWebEngineProcess to bundle (default: the one of the Qt used for the build)")
+# Locales shipped with WebEngine (the full set is about 35 MB).
+set(VRDASH_WEBENGINE_LOCALES en-US de)
+
 function(vrdash_bundle_qt)
     get_property(targets GLOBAL PROPERTY VRDASH_DASHBOARD_TARGETS)
     get_property(qml_dirs GLOBAL PROPERTY VRDASH_DASHBOARD_QML_DIRS)
@@ -52,6 +60,14 @@ function(vrdash_bundle_qt)
         set(qt_libdir ${qt_prefix}/lib/${CMAKE_LIBRARY_ARCHITECTURE}) # Debian multiarch
     endif()
 
+    # Used by the install script only if a bundled library is Qt WebEngine.
+    set(webengine_process ${VRDASH_WEBENGINE_PROCESS})
+    if(NOT webengine_process)
+        set(webengine_process ${QT6_INSTALL_PREFIX}/${QT6_INSTALL_LIBEXECS}/QtWebEngineProcess)
+    endif()
+    set(webengine_resources ${QT6_INSTALL_PREFIX}/${QT6_INSTALL_DATA}/resources)
+    set(webengine_locales ${QT6_INSTALL_PREFIX}/${QT6_INSTALL_TRANSLATIONS}/qtwebengine_locales)
+
     # The regexes end up inside a quoted string in the generated script: escape backslashes.
     string(REPLACE "\\" "\\\\" bundle_exclude "${VRDASH_BUNDLE_EXCLUDE}")