fix(plugins): isole les contributions plugin en erreur et durcit menus.ts

Le chargement de l'archive hello-plugin (build/hello-plugin-0.1.0.zip)
vidait la fenêtre principale : une contribution plugin fautive
remontait jusqu'au rendu global au lieu de rester locale à la cellule.
Ajoute un boundary local dans PluginLayoutCellView/PluginLayoutSelectorSection
et durcit menus.ts/loader.ts/registry.ts contre les entrées de menu ou
contributions malformées.

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

frontend/src/features/plugins/PluginLayoutCellView.tsx

@@ -10,6 +10,8 @@
  * calls from inside a plugin component).
  */
 
+import { Component, type ErrorInfo, type ReactNode } from "react";
+
 import type { CustomPluginLayoutCell, PluginAdmin } from "@/domain";
 import { useGateways } from "@/app/di";
 import { usePluginRuntime } from "./PluginRuntimeProvider";
@@ -25,6 +27,38 @@ interface PluginLayoutCellViewProps {
   onChooseAnotherLayout: () => void;
 }
 
+interface PluginLayoutErrorBoundaryProps {
+  resetKey: string;
+  fallback: ReactNode;
+  children: ReactNode;
+}
+
+class PluginLayoutErrorBoundary extends Component<
+  PluginLayoutErrorBoundaryProps,
+  { hasError: boolean }
+> {
+  state = { hasError: false };
+
+  static getDerivedStateFromError(): { hasError: boolean } {
+    return { hasError: true };
+  }
+
+  componentDidCatch(error: Error, errorInfo: ErrorInfo): void {
+    console.error("[plugin-layout] render failed", error, errorInfo);
+  }
+
+  componentDidUpdate(prevProps: PluginLayoutErrorBoundaryProps): void {
+    if (prevProps.resetKey !== this.props.resetKey && this.state.hasError) {
+      this.setState({ hasError: false });
+    }
+  }
+
+  render(): ReactNode {
+    if (this.state.hasError) return this.props.fallback;
+    return this.props.children;
+  }
+}
+
 export function PluginLayoutCellView({
   projectId,
   cell,
@@ -36,11 +70,11 @@ export function PluginLayoutCellView({
   const { registry } = usePluginRuntime();
   const gateways = useGateways();
   const availability = resolvePluginLayoutAvailability(registry, cell, installedPlugins);
+  const providerDisplayName =
+    registry.get(cell.pluginId)?.displayName ??
+    installedPlugins?.find((p) => p.id === cell.pluginId)?.displayName;
 
   if (availability !== "available") {
-    const providerDisplayName =
-      registry.get(cell.pluginId)?.displayName ??
-      installedPlugins?.find((p) => p.id === cell.pluginId)?.displayName;
     return (
       <PluginLayoutFallback
         cell={cell}
@@ -53,21 +87,35 @@ export function PluginLayoutCellView({
   }
 
   const Component = registry.layoutComponent(cell.pluginId, cell.layoutType)!;
-  return (
-    <Component
-      projectId={projectId}
-      nodeId={cell.id}
-      layoutType={cell.layoutType}
-      state={cell.state}
-      setState={onStateChange}
-      availability="available"
-      gateways={{
-        project: gateways.project,
-        git: gateways.git,
-        terminal: gateways.terminal,
-        agents: gateways.agent,
-        system: gateways.system,
-      }}
+  const fallback = (
+    <PluginLayoutFallback
+      cell={cell}
+      availability="incompatible"
+      providerDisplayName={providerDisplayName}
+      onOpenPlugins={onOpenPlugins}
+      onChooseAnotherLayout={onChooseAnotherLayout}
     />
   );
+  return (
+    <PluginLayoutErrorBoundary
+      resetKey={`${cell.pluginId}:${cell.layoutType}:${cell.id}`}
+      fallback={fallback}
+    >
+      <Component
+        projectId={projectId}
+        nodeId={cell.id}
+        layoutType={cell.layoutType}
+        state={cell.state}
+        setState={onStateChange}
+        availability="available"
+        gateways={{
+          project: gateways.project,
+          git: gateways.git,
+          terminal: gateways.terminal,
+          agents: gateways.agent,
+          system: gateways.system,
+        }}
+      />
+    </PluginLayoutErrorBoundary>
+  );
 }