every plugin route renders a workspace, and it is not a rule you can forget

an exclusionary rule, made structural. a plugin does not render a screen: it
contributes panels and says how they are arranged, and the shell renders
WorkspaceView around them.

    web/panels.ts   appRegistryMetas — at least one panel
    web/layout.ts   defaultLayout — how they are arranged

both required the moment web/ exists, and missing either is refused at discovery
by name and with the reason. tested:

    probeplug: has a web/ directory but is missing web/layout.ts.
    Every plugin route renders a Workspace: contribute panels and a layout,
    not a screen.

there is deliberately no way to export a component. one that could would be free
to render a bare div, a full-page form, or its own navigation, and the platform
would become a shell hosting strangers' layouts rather than one application.
non-compliance is not so much refused as unrepresentable — there is nowhere to
put a screen.

the shell registers <prefix> and <prefix>/:section, exactly as the core screens
do, so a plugin's sections stay addressable and cmd-clickable, and panels read
useParams independently rather than passing state between themselves.
appTypes.allowed is pinned to that plugin's own keys, so a persisted layout
naming something else falls back instead of rendering another plugin's panel
inside this screen.

the example plugin is rebuilt to model it — two panels, a layout, one of them
calling its own /api/example/ping through useClient — because the reference
implementation is what everyone copies.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

plugins/example/web/ExampleOverview.tsx

@@ -0,0 +1,27 @@
+import { useClient } from 'hooks/useClient';
+import { useQuery } from '@tanstack/react-query';
+
+// A panel, not a screen. It gets whatever space the layout gives it and knows nothing about routing.
+//
+// `useClient` comes from the platform's workspace packages, resolved because a plugin lives inside the
+// repository — no publishing, no version negotiation. This is the whole plugin↔host API in one line.
+export const ExampleOverview = () => {
+  const client = useClient();
+  const { data, isLoading } = useQuery({
+    queryKey: ['example', 'ping'],
+    queryFn: () => client.get<{ plugin: string; ok: boolean }>('/example/ping'),
+  });
+
+  return (
+    <div className="h-full overflow-auto p-6">
+      <h2 className="text-lg font-semibold text-duck-dark">Example</h2>
+      <p className="mt-1 text-sm text-duck-dark/60">
+        A panel from <code>plugins/example/web/</code>, rendered by the shell's <code>WorkspaceView</code>.
+      </p>
+      <div className="mt-4 rounded-md border border-duck-dark/10 bg-duck-dark/[0.02] p-3 font-mono text-xs">
+        <div className="mb-1 text-duck-dark/50">GET /api/example/ping</div>
+        {isLoading ? <span className="text-duck-dark/40">…</span> : <span>{JSON.stringify(data)}</span>}
+      </div>
+    </div>
+  );
+};