fix(download-server): harden qBittorrent privacy and reliability

- Enable AnonymousMode to hide client fingerprint from peers/trackers.
  Was disabled due to suspected stall issues, but the root cause was
  VPN port forwarding, not anonymity mode.

- Change MaxRatioAction from remove (1) to pause (0). Removing files
  on ratio completion risks data loss if Sonarr/Radarr hasn't imported
  yet. Pausing lets the arr services handle cleanup.

- Increase log file size from 65KB to 10MB for meaningful debug history.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: Test User

flake-modules/hosts/download-server-1/default.nix

@@ -1215,22 +1215,22 @@ EOF
                 "FileLogger\\Backup" = true;
                 "FileLogger\\DeleteOld" = true;
                 "FileLogger\\Enabled" = true;
-                "FileLogger\\MaxSizeBytes" = 66560;
+                "FileLogger\\MaxSizeBytes" = 10485760;  # 10MB
                 "FileLogger\\Path" = "/var/lib/qBittorrent/qBittorrent/data/logs";
               };
 
               BitTorrent = {
                 MergeTrackersEnabled = true;
                 "Session\\AddExtensionToIncompleteFiles" = true;
                 "Session\\AddTorrentToTopOfQueue" = true;
-                "Session\\AnonymousModeEnabled" = false;  # Disabled - was causing stalled torrents
+                "Session\\AnonymousModeEnabled" = true;  # Hide client fingerprint from peers/trackers
                 "Session\\DefaultSavePath" = "/media/downloads/complete";
                 "Session\\DisableAutoTMMByDefault" = false;
                 "Session\\DisableAutoTMMTriggers\\CategorySavePathChanged" = false;
                 "Session\\DisableAutoTMMTriggers\\DefaultSavePathChanged" = false;
                 "Session\\ExcludedFileNames" = "";
                 "Session\\GlobalMaxRatio" = 2;
-                "Session\\MaxRatioAction" = 1;  # Remove torrent and files after hitting ratio
+                "Session\\MaxRatioAction" = 0;  # Pause torrent after hitting ratio (Sonarr/Radarr handle cleanup)
                 "Session\\I2P\\Enabled" = false;  # Temporarily disabled to debug crashes
                 "Session\\I2P\\MixedMode" = true;
                 "Session\\IgnoreSlowTorrentsForQueueing" = true;