feat: arr-native distributed media sync + config architecture fixes

Arr sync (new):
- Media/arr_sync.sh — full mesh bidirectional sync across all HOST* nodes
  - Lidarr (MusicBrainz), Sonarr (TVDB), Radarr (TMDB) all handled in one script
  - Remote API keys read live from config.xml via SSH — never stored in conf files
  - Shared blocklist (DATA_DIR/arr_sync_blocklist.tsv) merged from all nodes at runtime
  - Graceful skip if arr not configured locally or not reachable on a remote node
  - --blocklist-add / --blocklist-remove / --blocklist-list management flags
- daily_sync_maintenance.sh — arr sync runs as explicit phase before rsync
- partnership_onboard.sh — Step 3 bootstraps merged library on both sides at onboard
- master.conf — ARR_SYNC_* config block, DOCKER_APPDATA_BASE

Rsync / cleanup:
- DEFAULT_RSYNC_OPTS — removed --delete; arr_cleanup.sh owns orphan enforcement
- lidarr_cleanup.sh — removed HOST1-only guard; runs on any node with Lidarr configured

Config architecture:
- HOST1/HOST2 hostnames moved from master_host*.conf → master.conf (not credentials)
- Sparse checkout now works correctly: each server only needs its own host conf
- detect_hosts() still resolves MY_ID + REMOTE_ID via master.conf hostname values

Bug fix:
- common.sh line 493 — watchdog toggle eval had broken quoting; all SYS_WATCHDOG_CHECK_*
  globals were silently set to empty instead of their configured values

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Media/lidarr_cleanup.sh

@@ -43,9 +43,8 @@
 #       The user accepts full responsibility — this is 100% intentional by design.
 #
 # ── HOST AWARENESS ────────────────────────────────────────────────────────────────────────────
-# Lidarr runs on HOST1 only — music library is HOST1's source of truth.
-# detect_hosts() sets MY_ID — if MY_ID != HOST1 script exits cleanly with no action.
-# LIDARR_URL, LIDARR_API_KEY, LIDARR_MUSIC_ROOT aliased by detect_hosts() automatically.
+# Runs on any node where Lidarr is configured — skips cleanly if LIDARR_URL/API_KEY not set.
+# detect_hosts() aliases LIDARR_URL, LIDARR_API_KEY, LIDARR_MUSIC_ROOT from HOST*_LIDARR_*.
 #
 # ── SAFEGUARDS ────────────────────────────────────────────────────────────────────────────────
 #   acquire_lock "wait"  — large scans take time, wait for previous run to finish
@@ -155,9 +154,9 @@ acquire_lock "wait"
 # detect_hosts() sets MY_ID and aliases LIDARR_URL, LIDARR_API_KEY, LIDARR_MUSIC_ROOT
 detect_hosts
 
-# Lidarr is HOST1 only — exit cleanly on any other host
-if [[ "$MY_ID" != "HOST1" ]]; then
-    log "Lidarr runs on HOST1 only — skipping on $MY_ID ($LOCAL_SERVER_NAME)"
+# Skip if Lidarr is not configured on this host
+if [[ -z "${LIDARR_URL:-}" ]] || [[ -z "${LIDARR_API_KEY:-}" ]]; then
+    log "Lidarr not configured on $MY_ID ($LOCAL_SERVER_NAME) — skipping"
     exit 0
 fi
 
@@ -182,8 +181,7 @@ if [[ ! -d "$LIDARR_MUSIC_ROOT" ]]; then
     exit 1
 fi
 
-log "Lidarr URL:   $LIDARR_URL"
-log "Music root:   $LIDARR_MUSIC_ROOT"
+echo "  $MY_ID ($LOCAL_SERVER_NAME) — $LIDARR_URL"
 
 [[ "$DRY_RUN" == true ]]    && warn "DRY RUN — no files will be deleted"
 [[ "$I_KNOW" == true ]]     && warn "OVERRIDE — --i-know-what-im-doing active"
@@ -310,7 +308,7 @@ fi
 # Safety Layer 3 — API version check
 check_arr_version "$LIDARR_URL" "$LIDARR_API_KEY" "v1" "$LIDARR_VERSION_MAJOR" "Lidarr" || exit 1
 
-log "Querying Lidarr API: $LIDARR_URL"
+echo "  Querying Lidarr API..."
 
 # Fetch all artists
 ARTIST_RESPONSE=$(lidarr_api "artist") || {
@@ -371,7 +369,7 @@ if [[ "$TRACKED_COUNT" -eq 0 ]]; then
     exit 1
 fi
 
-warn "Lidarr tracks $TRACKED_COUNT files across $ARTIST_COUNT artists"
+echo "  $ARTIST_COUNT artists | $TRACKED_COUNT tracked files"
 
 # Safety Layer 6 — percentage drop vs last known count
 if [[ -f "$LIDARR_TRACKED_COUNT_FILE" ]]; then
@@ -399,9 +397,7 @@ echo "$TRACKED_COUNT" > "$LIDARR_TRACKED_COUNT_FILE"
 # ==============================================================================================
 echo ""
 echo "━━━ $ICON_CLEAN Scanning Music Root ━━━"
-log "Root:       $LIDARR_MUSIC_ROOT"
-log "Orphan age: ${LIDARR_ORPHAN_AGE} days"
-log "Protected:  ${LIDARR_PROTECTED_PATTERNS[*]}"
+echo "  Root: $LIDARR_MUSIC_ROOT | Orphan age: ${LIDARR_ORPHAN_AGE} days"
 echo ""
 
 START=$(date +%s)