feat(plugins): load image-owned catalogs and persistent app overlays

Co-Authored-By: Paperclip <noreply@paperclip.ing>

ui/src/components/PluginAppShellOverlays.tsx

@@ -0,0 +1,45 @@
+import { useAccountIdentity } from "@/api/companies-query";
+import { useCompany } from "@/context/CompanyContext";
+import { useDialogState } from "@/context/DialogContext";
+import { PluginSlotMount, usePluginSlots, type PluginSlotContext } from "@/plugins/slots";
+
+function AppShellEntries({ context }: { context: PluginSlotContext }) {
+  const { slots, errorMessage } = usePluginSlots({
+    slotTypes: ["appShellOverlay"],
+    companyId: context.companyId,
+  });
+  // Optional extensions must not replace the application's normal error UI.
+  if (errorMessage || slots.length === 0) return null;
+  return (
+    <aside className="plugin-app-shell-overlays" aria-label="Application extensions">
+      {slots.map((slot) => (
+        <PluginSlotMount
+          key={`${slot.pluginId}:${slot.pluginVersion}:${slot.id}`}
+          slot={slot}
+          context={context}
+          className="plugin-app-shell-overlay"
+        />
+      ))}
+    </aside>
+  );
+}
+
+/**
+ * One persistent mount in each application shell. Navigation preserves the
+ * plugin tree; changing account/company, signing out, or entering onboarding
+ * disposes it. Plugins must cancel their requests/subscriptions on disposal.
+ * Host context is display context, never proof of server authorization.
+ */
+export function PluginAppShellOverlays({ localTrusted = false }: { localTrusted?: boolean }) {
+  const { userId, settled } = useAccountIdentity();
+  const { selectedCompanyId, selectedCompany, loading } = useCompany();
+  const { onboardingOpen } = useDialogState();
+  const identity = localTrusted ? "local-board" : settled ? userId : null;
+  if (!identity || loading || onboardingOpen) return null;
+  return (
+    <AppShellEntries
+      key={JSON.stringify([identity, selectedCompanyId])}
+      context={{ companyId: selectedCompanyId, companyPrefix: selectedCompany?.issuePrefix ?? null }}
+    />
+  );
+}