Reorganize repository structure for better organization

- Move backend code to swingmusic/ folder
- Move client applications to root level (swingmusic-android, swingmusic-desktop, swingmusic-webclient)
- Remove intermediate backend/ and clients/ folders
- Update README with new folder structure and setup instructions
- Clean and organized repository layout

README.md

@@ -52,18 +52,16 @@ This repository includes client applications as submodules:
 
 ## 🚀 Quick Start
 
-### Prerequisites
-- Python 3.11+
-- FFmpeg (for audio processing)
-- libev (Linux/macOS)
-
-### Installation
+### Backend Setup
 
 ```bash
 # Clone the repository
-git clone https://github.com/Dvorinka/swingmusic-extended.git
+git clone --recurse-submodules https://github.com/Dvorinka/swingmusic-extended.git
 cd swingmusic-extended
 
+# Navigate to backend
+cd swingmusic
+
 # Install dependencies
 uv sync
 
@@ -86,6 +84,15 @@ docker run --name swingmusic \
   ghcr.io/Dvorinka/swingmusic-extended:latest
 ```
 
+### Client Applications
+
+```bash
+# Navigate to specific client
+cd swingmusic-android  # or swingmusic-desktop or swingmusic-webclient
+
+# Follow client-specific setup instructions in each README
+```
+
 ### Docker Compose
 
 ```yaml