Feature 4: Webinterface — React-Frontend, Discord-OAuth2, REST-API

- Discord-OAuth2-Login (identify-Scope, CSRF-State, signierte Session-Cookies, keine Token-Speicherung)
- REST-API: /api/devlogs (öffentlich), /api/commits (nur ADMIN_DISCORD_ID), /api/me
- React + Vite Frontend: Devlog-Archiv mit Mini-Markdown-Renderer, Commit-Tabelle, dunkles EcoGame-Theme
- Fastify liefert frontend/dist mit SPA-Fallback aus; Vite-Dev-Proxy für lokale Entwicklung
- Multi-Stage-Dockerfile (Frontend-Build im Image), neue Env-Vars in Compose + .env.example
- README: OAuth2-Setup (Redirect-URLs, Client Secret) und Frontend-Workflow

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

frontend/src/main.jsx

@@ -0,0 +1,13 @@
+import React from 'react';
+import ReactDOM from 'react-dom/client';
+import { BrowserRouter } from 'react-router-dom';
+import App from './App.jsx';
+import './style.css';
+
+ReactDOM.createRoot(document.getElementById('root')).render(
+    <React.StrictMode>
+        <BrowserRouter>
+            <App />
+        </BrowserRouter>
+    </React.StrictMode>
+);