feat: add XDG autostart support for automatic application launching

feat: implement demo mode for automated feature showcase
feat: add XEmbed system tray protocol for external application icons
feat: add window snapping to left and right halves
feat: add minimize/restore toggle with Alt+F9 keybinding
docs: update README with new features and configuration details
build: update build system for new autostart and demo modules

config/config.example

@@ -91,3 +91,16 @@ model = google/gemini-2.0-flash-exp:free
 # Can also be set via EXA_API_KEY environment variable
 # Sign up and get your key at: https://dashboard.exa.ai/api-keys
 # exa_api_key = your-exa-key-here
+
+[autostart]
+# Enable XDG autostart support (default: true)
+# Automatically starts applications from XDG autostart directories
+enabled = true
+
+# Scan XDG .desktop files (default: true)
+# Directories: /etc/xdg/autostart and ~/.config/autostart
+xdg_autostart = true
+
+# Additional directory for symlinks and scripts (default: ~/.config/dwn/autostart.d)
+# Create symlinks to binaries you want to start: ln -s /usr/bin/telegram-desktop ~/.config/dwn/autostart.d/
+path = ~/.config/dwn/autostart.d