Update language files with new and revised strings

Expanded and reorganized language keys in en.json, including improved labels for language selection, about dialog, and time range features. Added missing Portuguese language entry to es.json for consistency. Updated descriptions and placeholders for better clarity and user experience.

languages/en.json

@@ -1,4 +1,15 @@
 {
+  "language": {
+    "display_name": "English",
+    "select_language": "Select language:",
+    "current_language": "Current language: {language}",
+    "restart_required": "Language changes will take effect after restarting the application.",
+    "english": "English",
+    "spanish": "Español (Spanish)",
+    "portuguese": "Português (Portuguese)",
+    "help_text": "Select your preferred language for the interface.",
+    "restart_notice": "Language change will take effect after restarting the application."
+  },
   "app": {
     "title": "YTSage",
     "version": "v{version}",
@@ -134,11 +145,7 @@
     "main_configured": "Main proxy configured",
     "geo_configured": "Geo proxy configured"
   },
-  "language": {
-    "help_text": "Select your preferred language for the interface.",
-    "current_language": "Current Language:",
-    "restart_notice": "Language change will take effect after restarting the application."
-  },
+
   "download": {
     "preparing": "Preparing download...",
     "please_enter_url": "Please enter a URL first.",
@@ -179,25 +186,30 @@
   },
   "about": {
     "title": "About YTSage",
-    "version": "Version: {version}",
-    "description": "A modern YouTube downloader with advanced features",
-    "author": "Created with ❤️",
-    "license": "License: MIT",
+    "version": "Version {version}",
+    "description": "Modern YouTube downloader with clean PySide6 interface.",
+    "author": "By: {author}",
+    "github": "GitHub: {repo}",
     "system_info": "System Information",
-    "python_version": "Python Version: {version}",
-    "pyside_version": "PySide6 Version: {version}",
-    "ytdlp_version": "yt-dlp Version: {version}",
-    "ffmpeg_status": "FFmpeg Status: {status}",
-    "ffmpeg_available": "Available",
-    "ffmpeg_not_available": "Not Available",
-    "error_getting_info": "Error getting system information: {error}"
+    "loading": "🔄 Loading system information...",
+    "refresh": "🔄",
+    "refreshing": "🔄 Refreshing...",
+    "refresh_failed": "Refresh Failed",
+    "refresh_failed_message": "Could not refresh version information.",
+    "detected": "✓ Detected",
+    "missing": "✗ Missing",
+    "not_available": "Not Available"
   },
   "time_range": {
     "title": "Trim Video",
+    "time_range_group": "Time Range",
     "start_time": "Start Time (HH:MM:SS)",
     "end_time": "End Time (HH:MM:SS)",
     "start_placeholder": "00:00:00",
     "end_placeholder": "00:00:00",
+    "start_time_placeholder": "Start time (HH:MM:SS)",
+    "end_time_placeholder": "End time (HH:MM:SS)",
+    "force_keyframes": "Force keyframes at cut points",
     "help_text": "Set the start and end times to trim the video.\nLeave empty to download the full video.",
     "invalid_format": "Invalid time format. Use HH:MM:SS format.",
     "start_after_end": "Start time cannot be after end time."