Add output format selection to settings

Introduces new settings for forcing output format when merging videos, allowing users to select a preferred format (mp4, webm, mkv). Updates all language files with relevant translations, adds UI controls in the settings dialog, persists settings via ConfigManager, and passes options through the download workflow to yt-dlp.

src/gui/ytsage_gui_main.py

@@ -124,6 +124,9 @@ class YTSageApp(QMainWindow, FormatTableMixin, VideoInfoMixin):  # Inherit from
         self.speed_limit_unit_index = 0  # Store speed limit unit index (0: KB/s, 1: MB/s)
         self.download_section = None
         self.force_keyframes = False
+        # Initialize output format settings
+        self.force_output_format = ConfigManager.get("force_output_format") or False
+        self.preferred_output_format = ConfigManager.get("preferred_output_format") or "mp4"
 
         self.init_ui()
         self.setStyleSheet(
@@ -768,8 +771,18 @@ class YTSageApp(QMainWindow, FormatTableMixin, VideoInfoMixin):  # Inherit from
                     f"Speed limit updated to: {self.speed_limit_value} {['KB/s', 'MB/s'][self.speed_limit_unit_index] if self.speed_limit_value else 'None'}"
                 )
 
+            # Update Output Format Settings
+            new_force_format = dialog.get_force_format_enabled()
+            new_preferred_format = dialog.get_preferred_format()
+            format_changed = False
+            if new_force_format != self.force_output_format or new_preferred_format != self.preferred_output_format:
+                self.force_output_format = new_force_format
+                self.preferred_output_format = new_preferred_format
+                format_changed = True
+                logger.info(f"Output format settings updated - Force: {self.force_output_format}, Preferred: {self.preferred_output_format}")
+
             # Update Tooltip if anything changed
-            if path_changed or limit_changed:
+            if path_changed or limit_changed or format_changed:
                 limit_text = "None"
                 if self.speed_limit_value:
                     limit_text = f"{self.speed_limit_value} {['KB/s', 'MB/s'][self.speed_limit_unit_index]}"
@@ -876,6 +889,8 @@ class YTSageApp(QMainWindow, FormatTableMixin, VideoInfoMixin):  # Inherit from
             force_keyframes=self.force_keyframes,  # Pass the force keyframes setting
             proxy_url=self.proxy_url,  # Pass the proxy URL
             geo_proxy_url=self.geo_proxy_url,  # Pass the geo-verification proxy URL
+            force_output_format=self.force_output_format,  # Pass force output format setting
+            preferred_output_format=self.preferred_output_format,  # Pass preferred format
         )
 
         # Connect signals