Optimize playlist extraction with yt-dlp flat-playlist

Switches to using yt-dlp's --flat-playlist and --dump-single-json for faster initial playlist info extraction. Now fetches minimal info for all videos quickly, then retrieves full details for the first video only to populate format information, improving performance and reducing unnecessary data processing.

src/gui/ytsage_gui_main.py

@@ -1952,7 +1952,9 @@ class YTSageApp(QMainWindow, FormatTableMixin, VideoInfoMixin):  # Inherit from
                 url = f"https://www.youtube.com/playlist?list={playlist_id}"
 
             # Build command for basic info extraction
-            cmd = [yt_dlp_path, "--dump-json", "--no-warnings", url]
+            # Use --flat-playlist for fast initial extraction of playlist info + --dump-single-json
+            # This fetches minimal info for all videos quickly without downloading full details for each
+            cmd = [yt_dlp_path, "--dump-single-json", "--flat-playlist", "--no-warnings", url]
 
             # Add cookies if available
             if self.cookie_file_path:
@@ -1998,21 +2000,12 @@ class YTSageApp(QMainWindow, FormatTableMixin, VideoInfoMixin):  # Inherit from
 
             self.signals.update_status.emit(_("main_ui.analyzing_processing_data"))
 
-            if first_info.get("_type") == "playlist" or len(json_lines) > 1:
+            if first_info.get("_type") == "playlist":
                 # Handle playlist
                 self.is_playlist = True
                 self.playlist_info = first_info
                 self.selected_playlist_items = None
-                self.playlist_entries = []
+                self.playlist_entries = first_info.get("entries", [])
-
-                # Parse all entries
-                for line in json_lines:
-                    try:
-                        entry = json.loads(line)
-                        if entry.get("_type") != "playlist":  # Skip playlist metadata
-                            self.playlist_entries.append(entry)
-                    except json.JSONDecodeError:
-                        continue
 
                 if not self.playlist_entries:
                     logger.error("Playlist contains no valid videos.")
@@ -2021,8 +2014,31 @@ class YTSageApp(QMainWindow, FormatTableMixin, VideoInfoMixin):  # Inherit from
                     self.signals.playlist_select_btn_visible.emit(False)
                     return
 
-                # Use first video for format information
+                # Even with flat-playlist, we need one video's formats to populate the table.
-                self.video_info = self.playlist_entries[0]
+                # Just use the first video URL to get full details quickly.
+                self.signals.update_status.emit(_("main_ui.analyzing_fetching_first_video"))
+                first_video_entry = self.playlist_entries[0]
+                first_video_url = first_video_entry.get("url")
+                
+                # Fetch full info for just the first video to get formats
+                cmd_single = [yt_dlp_path, "--dump-single-json", "--no-warnings", first_video_url]
+                 # Add cookies & proxy to this single request too
+                if self.cookie_file_path:
+                    cmd_single.extend(["--cookies", str(self.cookie_file_path)])
+                elif self.browser_cookies_option:
+                    cmd_single.extend(["--cookies-from-browser", self.browser_cookies_option])
+                if self.proxy_url:
+                    cmd_single.extend(["--proxy", self.proxy_url])
+                if self.geo_proxy_url:
+                    cmd_single.extend(["--geo-verification-proxy", self.geo_proxy_url])
+                    
+                result_single = subprocess.run(cmd_single, capture_output=True, text=True, timeout=60, creationflags=SUBPROCESS_CREATIONFLAGS)
+                
+                if result_single.returncode == 0:
+                     self.video_info = json.loads(result_single.stdout)
+                else:
+                    # Fallback to whatever minimal info we have, might fail table population
+                     self.video_info = first_video_entry
 
                 # Update playlist info label
                 playlist_text = _("playlist.display_format",