feat(panels): render each panel's state classes from the store

A panel's collapsed, dock-pinned, dock-pinned-top, layout-auto-collapsed
and accordion-collapsed classes are drawn by its root's v-panel-state from
the gev-panel-chrome store. PanelChrome, its restore, the layout
controller, both rails and the side accordion present each panel's state
there instead of writing its classes; the rails call onCollapse(panel,
{collapsed, auto}). The directive applies a change in a synchronous
watcher, since the rails measure a panel in the task that opens or closes
it.

Destroying the chrome inside Cockpit now puts back the panels Cockpit's
entry closed while it can still present them. Without a shell, the voice
tools' set_panel_open reports that there is no panel to open. QA scripts
present the states they set instead of writing the classes.

scripts/qa-cockpit-utility.mjs

@@ -1799,7 +1799,7 @@ try {
     manager._setCockpitDisplayPortalActive(false);
     document.body.classList.remove('cockpit-mode');
     await waitFrames();
-    standard.classList.remove('collapsed');
+    manager._presentPanel(standard, { collapsed: false });
     standard.style.height = '120px';
     standard.style.maxHeight = '120px';
     standard.style.overflowY = 'auto';
@@ -1834,7 +1834,7 @@ try {
     cockpit.style.height = priorCockpitHeight;
     cockpit.style.maxHeight = priorCockpitMaxHeight;
     cockpit.style.overflowY = priorCockpitOverflow;
-    standard.classList.toggle('collapsed', standardWasCollapsed);
+    manager._presentPanel(standard, { collapsed: standardWasCollapsed });
     return {
       standardBefore,
       standardAfter,