NextGraph integration (WIP), broker banner, and feature-based architecture

- Add NextGraph data layer with @ng-org/orm, SHEX shapes (Event, UserProfile,
  Participation), session management, and FestipodDataContext with dual-mode
  operation (connected via NextGraph or local seed data)
- Add BrokerBanner and NgStatus components showing connection status
- Refactor to feature-based architecture: organize code by business domain
  (event, user, home, auth, workshop, meeting, notification) instead of
  technical layer. Modules only import from shared/, never from each other
- Collocate BDD features and step definitions with their modules: event-specific
  steps in event/steps/, user steps in user/steps/, shared generic steps remain
  in shared/steps/
- Set up multi-layer BDD structure (frontend/backend/e2e steps per module)
- Add project documentation (AGENTS.md, .project/knowledge/)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/app/App.tsx

@@ -0,0 +1,57 @@
+import React from 'react';
+import { RouterProvider, useRouter } from './router';
+import { ThemeProvider } from '../shared/context/ThemeContext';
+import { NextGraphProvider } from '../shared/context/NextGraphContext';
+import { FestipodDataProvider } from '../shared/context/FestipodDataContext';
+import { Gallery } from './components/Gallery';
+import { DemoMode } from './components/DemoMode';
+import { SpecsPage } from './components/specs';
+
+function AppContent() {
+  const { route, navigate, goBack } = useRouter();
+
+  if (route.page === 'demo') {
+    return (
+      <DemoMode
+        initialScreenId={route.screenId}
+        onBack={goBack}
+        onNavigateToStory={(storyId) => navigate({ page: 'specs', storyId })}
+      />
+    );
+  }
+
+  if (route.page === 'specs') {
+    return (
+      <SpecsPage
+        selectedFeatureId={route.featureId}
+        selectedStoryId={route.storyId}
+        onBack={goBack}
+        onSelectScreen={(screenId) => navigate({ page: 'demo', screenId })}
+        onSelectStory={(storyId) => navigate({ page: 'specs', storyId })}
+      />
+    );
+  }
+
+  return (
+    <Gallery
+      onSelectScreen={(screenId) => navigate({ page: 'demo', screenId })}
+      onShowSpecs={() => navigate({ page: 'specs' })}
+    />
+  );
+}
+
+export function App() {
+  return (
+    <ThemeProvider>
+      <NextGraphProvider>
+        <FestipodDataProvider>
+          <RouterProvider>
+            <AppContent />
+          </RouterProvider>
+        </FestipodDataProvider>
+      </NextGraphProvider>
+    </ThemeProvider>
+  );
+}
+
+export default App;