feat: two-stage Lidarr discovery + Emby→arr sync tools

Lidarr Discovery (playback_aware_lidarr_discovery.sh):
- Complete rewrite to two-stage pipeline: Stage 1 scores weekly Emby
  plays → top seeds; Stage 2 runs Last.fm getSimilar on seeds → scores
  candidates → adds top 0-5 to Lidarr
- Per-user influence cap (35%) prevents single listener dominating discovery
- Requires 2+ seeds to accept a candidate (single-seed skipped)
- Last.fm similarity limit 10 for tighter, higher-quality candidates
- 30-day reject cooldown history; MAX_ADDS=5 cap enforced
- Root folder fetched from Lidarr API at runtime (no config path)
- Added to WEEKLY_MAINTENANCE_SCRIPTS (uncommented)

Emby→arr sync tools (Tools/):
- emby_to_lidarr_sync.sh: finds Emby music artists not in Lidarr, adds them
  - Dirty tag filter: comma-list, feat./ft., &, vs, " - " patterns skipped
  - Root folder fetched from Lidarr API at runtime
- emby_to_sonarr_sync.sh: finds Emby series not in Sonarr, adds them
  - TVDB ID matching with title fallback
- emby_to_radarr_sync.sh: finds Emby movies not in Radarr, adds them
  - TMDB ID matching with title fallback
- All three: searchForMissing*: false (monitoring only, no searches triggered)
- All three documented in Tools/Manual-Tools.md

master.conf

@@ -380,7 +380,7 @@
         "Docker_Essentials/docker_weekly_restart.sh"    # weekly container restarts after sync
         "Docker_Essentials/docker_update_remaining.sh"  # pull updates for all other containers
         "unRAID_Essentials/clear_logs.sh"               # purge aged logs — Sunday only, low priority
-        #"Media/playback_aware_lidarr_discovery.sh"     # behavior-driven music discovery using weekly Emby playback history — WIP
+        "Media/playback_aware_lidarr_discovery.sh"      # behavior-driven music discovery using weekly Emby playback history
     )
 
 # Pull updates for all running containers NOT in daily/weekly restart lists.
@@ -940,6 +940,15 @@
     LIDARR_ART_SLEEP_BETWEEN=0.2        # seconds between fanart.tv API calls
 #   HOST*_FANART_API_KEY / HOST*_LASTFM_API_KEY — set in master_host*.conf
 
+# Lidarr discovery settings (playback_aware_lidarr_discovery.sh)
+    LIDARR_DISCOVERY_THRESHOLD=70         # score to accept candidate (0-100)
+    LIDARR_DISCOVERY_LOOKBACK_DAYS=7      # Emby play history window in days
+    LIDARR_DISCOVERY_MIN_PLAYS=3          # min plays in window before evaluating an artist
+    LIDARR_DISCOVERY_USER_CAP_PCT=35      # max % any single user can contribute to play score (prevents one listener dominating)
+    LIDARR_DISCOVERY_MAX_ADDS=5           # max artists to add per run — quality over bulk
+    LIDARR_DISCOVERY_REJECT_COOLDOWN=30   # days before re-evaluating a rejected artist
+    LIDARR_DISCOVERY_HISTORY="$DATA_DIR/lidarr_discovery_history.db"
+
 # Sonarr shared settings
     SONARR_ORPHAN_AGE=7             # days — files must be older than this before eligible for deletion
     SONARR_MAX_DELETE_GB=10         # require --i-know-what-im-doing if deletion exceeds this