Add FFmpeg updater module and GUI integration

Introduces a new FFmpeg updater module for checking and updating FFmpeg to the latest essentials build, with progress reporting and version comparison. Updates language files with new translation keys for the updater in multiple languages. Refactors Windows FFmpeg installation to use the new updater logic. Adds UpdaterTabWidget to the GUI dialogs for integration of the updater into the application's interface.

languages/en.json

@@ -99,7 +99,8 @@
     "cookies": "Login with Cookies",
     "custom_command": "Custom Command",
     "proxy": "Proxy",
-    "language": "Language"
+    "language": "Language",
+    "updater": "Updater"
   },
   "cookies": {
     "help_text": "Choose how to provide cookies for logging in.\nThis allows downloading of private videos and premium quality audio.",
@@ -466,5 +467,25 @@
     "redownload_confirm_title": "Redownload Video?",
     "redownload_confirm_message": "Download this video again using the same settings?\n\n{title}",
     "redownload_started": "Redownload started"
+  },
+  "ffmpeg_updater": {
+    "title": "FFmpeg Updater",
+    "current_version": "Current Version:",
+    "latest_version": "Latest Version:",
+    "status_up_to_date": "✓ Up to date",
+    "status_update_available": "⚠ Update available",
+    "status_not_installed": "✗ Not installed",
+    "status_idle": "Click 'Check for Updates' to get started",
+    "status_checking": "🔄 Checking for updates...",
+    "status_downloading": "⬇ Downloading FFmpeg...",
+    "status_installing": "⚙ Installing FFmpeg...",
+    "status_verifying": "✓ Verifying integrity...",
+    "check_updates": "Check for Updates",
+    "update_button": "Update FFmpeg",
+    "update_success": "FFmpeg successfully updated to version {version}!",
+    "update_failed": "Failed to update FFmpeg. Please try again.",
+    "check_failed": "Failed to check for updates. Please check your internet connection.",
+    "install_first": "FFmpeg is not installed. Click Update to install.",
+    "description": "Keep FFmpeg up to date for the best performance and compatibility."
   }
 }