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.

src/voice/gevActions.js

@@ -817,7 +817,17 @@ export function createGevActionRunner({
           ...(!applied ? { error: say } : {}),
         };
       }
-      setPanelOpen(styleManager, panelId, open);
+      if (!setPanelOpen(styleManager, panelId, open)) {
+        const say = 'There is no panel to open here.';
+        return {
+          ok: false,
+          action: 'set_panel_open',
+          panelId,
+          open,
+          say,
+          error: say,
+        };
+      }
       return { ok: true, action: 'set_panel_open', panelId, open };
     }
 
@@ -3143,13 +3153,14 @@ function normalizeAircraftClassFilter(value) {
   return raw.replace(/[\s-]+/g, '') === TR3B_CLASS ? TR3B_CLASS : raw;
 }
 
+/**
+ * @returns {boolean} Whether a shell took the change: its panel chrome owns
+ *   panel state, so without one there is no panel to open.
+ */
 function setPanelOpen(styleManager, panelId, open) {
-  if (styleManager && typeof styleManager.setPanelCollapsed === 'function') {
-    styleManager.setPanelCollapsed(panelId, !open, { explicit: true });
-  } else {
-    const panel = document.getElementById(panelId);
-    if (panel) panel.classList.toggle('collapsed', !open);
-  }
+  if (typeof styleManager?.setPanelCollapsed !== 'function') return false;
+  styleManager.setPanelCollapsed(panelId, !open, { explicit: true });
+  return true;
 }
 
 function normalizeContextMode(value) {