feat: Add comprehensive documentation

Add JSDoc docstrings to all public functions, methods, and classes throughout the codebase. This includes components, context providers, pages, utility functions, and the API client.

Update the main README.md to be a complete guide for new developers, covering the project's purpose, setup, and usage. This includes adding a "Project Purpose" section, clarifying the "Quick Start" and "How It Works" sections, and updating the "Features Roadmap."

Author: google-labs-jules[bot]

README.md

@@ -11,12 +11,16 @@
 
 **A professional, open-source content management system designed for creating beautiful tutorial websites with zero hassle.**
 
-[Features](#-features) • [Quick Start](#-quick-start) • [Customization](#-customization) • [Documentation](#-documentation) • [License](#-license)
+[Project Purpose](#-project-purpose) • [Features](#-features) • [Quick Start](#-quick-start) • [Customization](#-customization) • [Documentation](#-documentation) • [License](#-license)
 
 </div>
 
 ---
 
+## 🎯 Project Purpose
+
+The Linux Tutorial CMS is a modern, open-source platform designed for creating and managing high-quality, interactive tutorial websites. It combines a high-performance Rust backend with a flexible React frontend to provide a seamless experience for both content creators and learners. The primary goal of this project is to offer a fully customizable, easy-to-use solution for educational content that is both beautiful and fast.
+
 ## ✨ Features
 
 ### 🎨 Beautiful Default Design
@@ -89,15 +93,23 @@ npm run dev
 
 ### Admin-Anmeldung
 
-Der Backend-Server erstellt kein Standardkonto. Setze daher vor dem Start die Umgebungsvariablen `ADMIN_USERNAME` und `ADMIN_PASSWORD` (mindestens 12 Zeichen).
+To get started, you need to create a `.env` file in the `backend` directory. This file will store the necessary environment variables for the application to run correctly.
 
-```bash
-# Beispiel
-export ADMIN_USERNAME=deinadmin
-export ADMIN_PASSWORD=einSicheresPasswort123!
+**Example `backend/.env` file:**
+
+```env
+# The connection string for the SQLite database.
+DATABASE_URL=sqlite:./cms.db
+
+# A secret key for signing JWT tokens. You can generate a strong secret using a password manager or a command-line tool.
+JWT_SECRET=your-super-secret-key-that-is-at-least-32-characters-long
+
+# The credentials for the default admin account.
+ADMIN_USERNAME=admin
+ADMIN_PASSWORD=your-secure-password
 ```
 
-Passe die Werte entsprechend deiner Umgebung an und starte den Server danach neu.
+Once you have created the `.env` file, you can start the backend server.
 
 ---
 
@@ -161,6 +173,8 @@ All editable content is stored as **JSON objects** that you can modify through a
 
 **No database migrations needed** - just edit the JSON and save! ✨
 
+The content you edit in the admin panel is saved to the SQLite database. When a user visits the website, the React frontend fetches this content from the backend API and dynamically renders the pages. This architecture allows for a fast, modern user experience while still providing a simple and powerful content management system.
+
 ---
 
 ## 🎨 Customization
@@ -362,14 +376,14 @@ This project is licensed under the **MIT License** - see the [LICENSE](LICENSE)
 
 ## 🌟 Features Roadmap
 
+- [x] Dark mode theme
+- [x] Search functionality
 - [ ] Multi-language support
-- [ ] Dark mode theme
 - [ ] Markdown editor with live preview
 - [ ] Image upload and management
 - [ ] SEO optimization tools
 - [ ] Analytics dashboard
 - [ ] Comment system
-- [ ] Search functionality
 
 ---