Add Sonarr discovery; wire search commands to all arr adds

- New: Media/playback_aware_sonarr_discovery.sh — two-stage TV show
  discovery using Emby episode play history → TMDB TV recommendations.
  Multi-user aware: diversity score (0-50) is primary seed driver so one
  user binge-watching alone cannot dominate. Per-user episode cap (default 8)
  limits single-user volume contribution. TMDB→TVDB via external_ids for
  reliable Sonarr lookup. monitor=future by default.

- Add to WEEKLY_MAINTENANCE_SCRIPTS; Sonarr discovery config block in
  master.conf (threshold=52, lookback=14d, max_adds=3, user_ep_cap=8).

- Fix: all arr add scripts were not triggering searches after adding.
  Added _radarr_command/_lidarr_command/_sonarr_command helpers and fire
  MoviesSearch/ArtistSearch/SeriesSearch immediately after each successful
  add. Affects: playback_aware_radarr_discovery.sh, emby_to_lidarr_sync.sh,
  emby_to_radarr_sync.sh, emby_to_sonarr_sync.sh.

Tools/emby_to_radarr_sync.sh

@@ -100,6 +100,14 @@ _radarr_post() {
         "${RADARR_URL}/api/v3/movie" 2>/dev/null
 }
 
+_radarr_command() {
+    curl -sf --max-time 20 -X POST \
+        -H "X-Api-Key: $RADARR_API_KEY" \
+        -H "Content-Type: application/json" \
+        -d "$1" \
+        "${RADARR_URL}/api/v3/command" 2>/dev/null
+}
+
 # Episode/garbage title filter — catches anime episodes stored as individual files
 # in the Movies library, fansub release names, and codec metadata strings.
 _is_episode_title() {
@@ -272,6 +280,8 @@ for name in "${SORTED_MISSING[@]}"; do
     RESULT=$(_radarr_post "$PAYLOAD")
 
     if echo "$RESULT" | jq -e '.id' >/dev/null 2>&1; then
+        MOVIE_ID=$(echo "$RESULT" | jq -r '.id')
+        _radarr_command "{\"name\":\"MoviesSearch\",\"movieIds\":[${MOVIE_ID}]}" >/dev/null
         log "  $ICON_DONE Added: $RADARR_TITLE"
         (( ADDED++ ))
     else