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/ui/panelRails.test.mjs

@@ -7,6 +7,7 @@ import {
   layoutRightPanelRail,
   measurePanelNaturalHeight,
 } from './panelRails.js';
+import { applyPanelState, readPanelState } from './rail/panelState.js';
 
 test('Display uses an inner scroll body only in Cyber', () => {
   const body = { scrollTop: 95 };
@@ -169,7 +170,11 @@ function fixture(
       matchMedia: () => ({ matches: mobile }),
       getComputedStyle: (node) => node.computed,
     },
-    onCollapse: (panel) => collapsed.push(panel.id),
+    // The owner presents the patch; the panel's root draws it at once.
+    onCollapse: (panel, patch) => {
+      collapsed.push(panel.id);
+      applyPanelState(panel, { ...readPanelState(panel), ...patch });
+    },
     onRetry: () => {
       retries += 1;
     },