feat(linux): add README for AirPods Linux Native application with setup and usage instructions

linux/README.md

@@ -0,0 +1,50 @@
+# AirPods Linux Native (ALN)
+
+A native Linux application to control your AirPods, with support for:
+
+- Noise Control modes (Off, Transparency, Adaptive, Noise Cancellation)
+- Conversational Awareness
+- Battery monitoring
+- Auto play/pause on ear detection
+- Seamless handoff between phone and PC
+
+## Prerequisites
+
+1. Your phone's Bluetooth MAC address (can be found in Settings > About Device)
+2. Qt6 packages
+
+   ```bash
+   sudo pacman -S qt6-base qt6-connectivity qt6-multimedia-ffmpeg qt6-multimedia # Arch Linux / EndeavourOS
+   ```
+
+## Setup
+
+1. Edit `main.h` and update `PHONE_MAC_ADDRESS` with your phone's Bluetooth MAC address:
+
+   ```cpp
+   #define PHONE_MAC_ADDRESS "XX:XX:XX:XX:XX:XX"  // Replace with your phone's MAC
+   ```
+
+2. Build the application:
+
+   ```bash
+   mkdir build
+   cd build
+   cmake ..
+   make -j $(nproc)
+   ```
+
+3. Run the application:
+
+   ```bash
+   ./applinux
+   ```
+
+## Usage
+
+- Left-click the tray icon to view battery status
+- Right-click to access the control menu:
+  - Toggle Conversational Awareness
+  - Switch between noise control modes
+  - View battery levels
+  - Control playback