Fix dead-variable and exit-code bugs found in codebase-wide audit

Same audit as the orchestrator standardization pass (2a062e5), extended to
every remaining script. Found the same class of bug independently recurring:
ramdisk_stop.sh checked $LOG (nothing assigns it, should be $ENABLE_LOGGING),
partnership_onboard.sh checked $LOG_MODE (same issue), emby_session_report.sh
checked $TRANSCODE_PCT which was never computed so the high-transcode alert
could never fire, and storage_migrate.sh never called detect_hosts() so
$MY_ID was empty, silently breaking the post-migration host*.conf update.
partnership_manager.sh used `local` at top-level script scope (invalid outside
a function) and had two master.conf path references missing "Configurations/".

Along the way: several scripts (share_setup.sh, conf_sync.sh,
downloaders_reset.sh, transcode_cleanup.sh, transcode_manager.sh,
remote_arr_cache_writer.sh, upgrade_webhook_handler.sh) had no explicit
trailing exit code, so they always reported success regardless of real
failures. play_state_sync.sh was missing the partnership gate its own header
documented, so remote play-state sync ran even with PARTNERSHIP_ENABLED=false;
it also always exited 0 on sync errors. arr_profile_enforcer.sh and
webhook_setup.sh hand-rolled their own flag parsing instead of common.sh's
parse_args, so --log silently did nothing on either.

system_watchdog.sh was itself an un-standardized mini-orchestrator — converted
to the shared run_orch_child()/JOB_PASS/JOB_FAIL pattern, added the missing
failure notification, and fixed dry-run to pass --dry-run down to children
instead of skipping them outright. Also fixed a stale webgui_watchdog.sh path
in master.conf.template that would break system_watchdog.sh on any fresh
install.

Closed a sibling-drift gap: radarr_cleanup.sh and sonarr_cleanup.sh were
missing lidarr_cleanup.sh's tracked-count percentage-drop safety gate and its
"not configured on this host, skip cleanly" guard — both now match Lidarr's
7-gate model.

Configurations/master.conf

@@ -1145,6 +1145,9 @@
 # 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
+    SONARR_MIN_TRACKED_PCT=80       # abort if tracked count drops below this % of last run
+                                    # protects against API returning partial data on a bad day
+    SONARR_TRACKED_COUNT_FILE="$DATA_DIR/sonarr_tracked.count"
     SONARR_EXTENSIONS=("mkv" "mp4" "avi" "m4v" "ts" "wmv" "mov")
     SONARR_PROTECTED_PATTERNS=(
         # Subtitles
@@ -1168,6 +1171,9 @@
 # Radarr shared settings
     RADARR_ORPHAN_AGE=7             # days — files must be older than this before eligible for deletion
     RADARR_MAX_DELETE_GB=15         # require --i-know-what-im-doing if deletion exceeds this
+    RADARR_MIN_TRACKED_PCT=80       # abort if tracked count drops below this % of last run
+                                    # protects against API returning partial data on a bad day
+    RADARR_TRACKED_COUNT_FILE="$DATA_DIR/radarr_tracked.count"
     RADARR_EXTENSIONS=("mkv" "mp4" "avi" "m4v" "wmv" "mov")
     RADARR_PROTECTED_PATTERNS=(
         # Subtitles