Green Up: scope panel-group check to panel-backed tabs

Corporate Tools is the first PCDetail tab that mounts no PluginAssetPanels: it is permission-gated and renders a fixed action list, so no panel can land in it. The vocabulary check asserted every tabs.push key appears in RENDERED_GROUPS, which cd70556 broke by adding that tab.

Adding 'corptools' to the vocabulary would have made it a legal panel group with no panel host - fetched, held, rendered nowhere - the silent-drop failure this file exists to catch, and it would also have failed the server-vocabulary check against ASSET_PANEL_GROUPS. So the invariant is narrowed to panel-backed tabs instead, with a mirror check that any tab mounting a PluginAssetPanels must have its group rendered.

frontend/src/components/panelGroups.spec.js

@@ -29,12 +29,25 @@ function pcDetailSource() {
   return read('../../../plugins/computers/frontend/views/PCDetail.vue')
 }
 
+// The tabs that actually HOST panels - those where PCDetail mounts a
+// PluginAssetPanels for the group. A tab is only bound by the vocabulary if a
+// panel can land in it. Corporate Tools is the first tab that hosts none: it is
+// permission-gated and renders a fixed action list, so RENDERED_GROUPS has
+// nothing to say about it and requiring it there would make 'corptools' a legal
+// panel group with no panel host - fetched, held, rendered nowhere, which is
+// the very failure this file exists to catch.
+function panelHostedGroups(source) {
+  return [...source.matchAll(/group="([a-z]+)"/g)].map((match) => match[1])
+}
+
 describe('panel group vocabulary', () => {
-  it('renders a group for every tab PCDetail offers', () => {
+  it('renders a group for every panel-backed tab PCDetail offers', () => {
     const groups = renderedGroups()
     const source = pcDetailSource()
+    const hosted = panelHostedGroups(source)
     const tabKeys = [...source.matchAll(/tabs\.push\(\{\s*key:\s*'([a-z]+)'/g)]
       .map((match) => match[1])
+      .filter((key) => hosted.includes(key))
 
     expect(tabKeys.length).toBeGreaterThan(0)
     for (const key of tabKeys) {
@@ -42,6 +55,19 @@ describe('panel group vocabulary', () => {
     }
   })
 
+  it('never hosts panels in a group this build does not render', () => {
+    // The mirror of that exemption, so opting a tab out of panels cannot become
+    // a loophole: the moment a tab mounts a PluginAssetPanels, its group MUST
+    // be rendered, or the panels are fetched and dropped with nothing logged.
+    const groups = renderedGroups()
+    const hosted = panelHostedGroups(pcDetailSource())
+
+    expect(hosted.length).toBeGreaterThan(0)
+    for (const group of hosted) {
+      expect(groups).toContain(group)
+    }
+  })
+
   it('gives every rendered group somewhere to actually show', () => {
     // A group in RENDERED_GROUPS with no v-show block is the mirror failure:
     // the panel is kept rather than dropped, but still appears nowhere.