Bump version to 4.9.0b

Update version references from 4.8.3 to 4.9.0b in __init__.py, main app, and About dialog to prepare for the next beta release.

src/__init__.py

@@ -4,5 +4,5 @@ YTSage - YouTube Video Downloader
 A modern, user-friendly YouTube video downloader built with PySide6.
 """
 
-__version__ = "4.8.3"
+__version__ = "4.9.0b"
 __author__ = "oop7"

src/gui/ytsage_gui_dialogs/ytsage_dialogs_base.py

@@ -157,7 +157,7 @@ class AboutDialog(QDialog):
         layout.addWidget(title_label)
 
         version_label = QLabel(
-            f"<span style='color: #cccccc; font-size: 13px; font-weight: normal;'>Version {getattr(self._parent, 'version', '4.8.3')}</span>"
+            f"<span style='color: #cccccc; font-size: 13px; font-weight: normal;'>Version {getattr(self._parent, 'version', '4.9.0b')}</span>"
         )
         version_label.setAlignment(Qt.AlignmentFlag.AlignCenter)
         layout.addWidget(version_label)

src/gui/ytsage_gui_main.py

@@ -75,7 +75,7 @@ class YTSageApp(QMainWindow, FormatTableMixin, VideoInfoMixin):  # Inherit from
         else:
             logger.info(f"Using yt-dlp from: {ytdlp_path}")
 
-        self.version = "4.8.3"
+        self.version = "4.9.0b"
         self.check_for_updates()
 
         # Check for auto-updates if enabled