feat: added sound effects support to themes

Signed-off-by: Boris Yumankulov <boria138@altlinux.org>

documentation/theme_guide/README.md

@@ -9,12 +9,13 @@
 - [Metadata](#metadata)
 - [Screenshots](#screenshots)
 - [Fonts and Icons](#fonts-and-icons)
+- [Sound Effects](#sound-effects)
 
 ---
 
 ## 📖 Overview
 
-Themes in `PortProtonQT` allow customizing the UI appearance. Themes are stored under:
+Themes in `PortProtonQT` allow customizing the UI appearance and sounds. Themes are stored under:
 
 - `~/.local/share/PortProtonQT/themes`.
 
@@ -34,6 +35,12 @@ Create a `styles.py` in the theme root. It should define variables or functions
 
 **Example:**
 ```python
+# Sound effects mapping
+SOUNDS = {
+    "app_start": "app_start.wav",           # Application startup
+    "app_exit": "app_exit.wav",             # Application exit
+}
+
 def custom_button_style(color1, color2):
     return f"""
     QPushButton {{
@@ -69,3 +76,19 @@ Folder: `images/screenshots/` — place UI screenshots there.
 - Icons: `images/icons/*.svg/.png`
 
 ---
+
+## 🔊 Sound Effects (optional)
+
+Folder: `sounds/` — place interface sound effects here.
+
+Supported formats:
+- `.wav` - Wave audio files
+
+Available sound events:
+- Interface sounds:
+  - `app_start.wav` - Application startup
+  - `app_exit.wav` - Application exit
+
+If a sound file is missing in a custom theme, the default sound from the standard theme will be used.
+
+---