Initial commit: Outlook-competitor desktop mail client

Tauri v2 (Rust backend, React/TypeScript frontend). IMAP/POP3/SMTP core,
Google OAuth (mail/calendar/contacts sync), CalDAV, local calendar with
recurrence, rules engine, contacts, tasks, unified inbox, context menus,
drag & drop, snooze, templates, and more.

src/main.tsx

@@ -0,0 +1,11 @@
+import { StrictMode } from 'react'
+import { createRoot } from 'react-dom/client'
+import './index.css'
+import App from './App.tsx'
+import { ComposeWindow } from './ComposeWindow.tsx'
+
+const isComposeWindow = new URLSearchParams(window.location.search).has('compose')
+
+createRoot(document.getElementById('root')!).render(
+  <StrictMode>{isComposeWindow ? <ComposeWindow /> : <App />}</StrictMode>,
+)