Add __init__.py for GUI dialogs package

Introduces src/gui/dialogs/__init__.py to organize and re-export dialog classes for the YTSage GUI. This file provides a structured overview of available dialogs and maintains backward compatibility by re-exporting all relevant classes.

src/gui/dialogs/__init__.py

@@ -0,0 +1,41 @@
+"""
+Dialog modules for YTSage GUI.
+
+This package contains all dialog classes organized by functionality:
+- Base dialogs (LogWindow, AboutDialog)
+- Settings dialogs (DownloadSettingsDialog, AutoUpdateSettingsDialog)
+- Update dialogs (YTDLPUpdateDialog, update threads)
+- FFmpeg dialogs (FFmpegCheckDialog, installation)
+- Selection dialogs (SubtitleSelectionDialog, PlaylistSelectionDialog)
+- Custom dialogs (CustomCommandDialog, CookieLoginDialog, etc.)
+"""
+
+# Re-export all dialog classes for backward compatibility
+from .ytsage_dialogs_base import LogWindow, AboutDialog
+from .ytsage_dialogs_settings import DownloadSettingsDialog, AutoUpdateSettingsDialog
+from .ytsage_dialogs_update import (VersionCheckThread, UpdateThread, YTDLPUpdateDialog, 
+                                   AutoUpdateThread)
+from .ytsage_dialogs_ffmpeg import FFmpegInstallThread, FFmpegCheckDialog
+from .ytsage_dialogs_selection import SubtitleSelectionDialog, PlaylistSelectionDialog, SponsorBlockCategoryDialog
+from .ytsage_dialogs_custom import (CustomCommandDialog, CookieLoginDialog, 
+                                   CustomOptionsDialog, TimeRangeDialog)
+
+__all__ = [
+    # Base dialogs
+    'LogWindow', 'AboutDialog',
+    
+    # Settings dialogs
+    'DownloadSettingsDialog', 'AutoUpdateSettingsDialog',
+    
+    # Update dialogs and threads
+    'VersionCheckThread', 'UpdateThread', 'YTDLPUpdateDialog', 'AutoUpdateThread',
+    
+    # FFmpeg dialogs
+    'FFmpegInstallThread', 'FFmpegCheckDialog',
+    
+    # Selection dialogs
+    'SubtitleSelectionDialog', 'PlaylistSelectionDialog', 'SponsorBlockCategoryDialog',
+    
+    # Custom functionality dialogs
+    'CustomCommandDialog', 'CookieLoginDialog', 'CustomOptionsDialog', 'TimeRangeDialog'
+]