♻️ refactor: implement Phase 1 folder-pattern compliance

- Rename App.tsx to app.tsx (kebab-case naming convention)
- Add barrel exports (index.ts) for src/hooks/
- Add barrel exports (index.ts) for src/components/dialogs/
- Add barrel exports (index.ts) for src/components/layout/
- Update renderer.tsx import to use lowercase app.tsx

This is Phase 1 of folder-pattern.md compliance: establishing proper
file naming conventions and barrel export patterns.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

apps/ui/src/renderer.tsx

@@ -1,8 +1,8 @@
-import { StrictMode } from "react";
-import { createRoot } from "react-dom/client";
-import App from "./App";
+import { StrictMode } from 'react';
+import { createRoot } from 'react-dom/client';
+import App from './app';
 
-createRoot(document.getElementById("app")!).render(
+createRoot(document.getElementById('app')!).render(
   <StrictMode>
     <App />
   </StrictMode>