Add Radarr discovery + tighten arr sync filters

- playback_aware_radarr_discovery.sh: new two-stage movie discovery
  using recently watched Emby movies as seeds and TMDB recommendations
  as the similarity engine; scores on recency + rating + vote count;
  adds HOST*_TMDB_API_KEY alias to detect_hosts() in common.sh

- emby_to_sonarr_sync.sh: restrict to SONARR_EMBY_LIBRARIES allowlist
  (Anime, Kids Shows, Stand-Up Comedy, TV shows) — excludes Youtube
  and Recorded Sports libraries; add garbage title filter for multi-
  season folder names (S01-S03) and bare bracket tags ([Prof])

- emby_to_radarr_sync.sh: add _is_episode_title filter to block anime
  episode files stored in Movies library (underscore/dot patterns,
  fansub bracket format, episode markers, codec metadata strings)

- emby_to_lidarr_sync.sh: add U+FFFD Unicode replacement character
  filter alongside the existing ASCII ? filter for encoding corruption

- master.conf: RADARR_DISCOVERY_* settings, SONARR/RADARR_EMBY_LIBRARIES
  allowlists, Radarr discovery added to WEEKLY_MAINTENANCE_SCRIPTS

Tools/emby_to_lidarr_sync.sh

@@ -116,6 +116,8 @@ _is_dirty_artist() {
     [[ "$1" == *" & "* ]]      && return 0
     [[ "$lower" == *" vs "* ]] && return 0
     [[ "$1" == *" - "* ]]      && return 0
+    [[ "$1" == *"?"* ]]        && return 0   # ASCII ? — encoding corruption
+    [[ "$1" == *$'\xef\xbf\xbd'* ]] && return 0   # U+FFFD replacement character — encoding corruption
     return 1
 }