Wire up unused config vars found in follow-up audit pass

TRANSCODE_LOG_RETENTION was documented as trimming the daily transcode log
but never referenced — log grew unbounded. TRANSCODE_ORPHAN_AGE was shown in
--status but never used, so empty session folders were deleted immediately
instead of after the documented grace period, risking a race against ffmpeg
creating a folder just before writing its first segment.

docker_watchdog.sh's daemon-health thresholds were only hardcoded fallbacks
despite comments claiming they were master.conf-configurable, and it
referenced a heartbeat feature that was never implemented (that's owned by
watchdog_orchestrator.sh, its caller) — added the three thresholds to
master.conf for real and removed the stale heartbeat claim.

Also added the missing HOSTN_PARTNERSHIP_SERVICES_STACK block to
host.conf.template (containers.sh already read it via detect_hosts, just
never had a template entry) and corrected play_state_sync.sh's doc comment
for PLAY_SYNC_TYPES' actual default.

Watchdogs/docker_watchdog.sh

@@ -82,7 +82,8 @@
 #
 # Silent When Healthy
 #   Runs 96 times per day. Producing output on every clean cycle would make
-#   logs useless. Output only when something needs attention or a heartbeat fires.
+#   logs useless. Output only when something needs attention — alive heartbeat
+#   is handled by watchdog_orchestrator.sh, the caller, not this script.
 #
 # ==============================================================================================
 # OPERATIONAL SAFEGUARDS
@@ -196,8 +197,9 @@
 #   WATCHDOG_BATCH_NOTIFY
 #       Collect cycle events and send as one notification (default: true)
 #
-#   DOCKER_WATCHDOG_HEARTBEAT_HOURS
-#       Hours between alive heartbeat log entries
+#   WATCHDOG_DAEMON_TIMEOUT / WATCHDOG_DAEMON_STRIKE_LIMIT / WATCHDOG_DAEMON_RESTART_WAIT
+#       Docker daemon health check: command timeout, strikes before restart attempt,
+#       seconds to wait after restart before verifying
 #
 #   DOCKER_WATCHDOG_INTENTIONAL_FILE
 #       Path to intentional stops state file (STATE_DIR). Containers in this file