rename appdata-Failover→appdata-Fallback in docs; critical sync 15→30min; transcode 3→7min

appdata-Failover → appdata-Fallback:
  All .md files updated — scripts and confs already used appdata-Fallback.
  Share was renamed; docs were the only stale references.

critical_sync_maintenance.sh: */15 → */30, 96/day → 48/day:
  critical_sync_maintenance.sh header, master.conf, host1/2.conf comments,
  Orchestrators README, User Script Plug-in README, Partnership README/manual/script,
  Docker_Essentials README/downloaders_reset.sh, Fallback README,
  weekly_sync_maintenance.sh, user_script_plug-in.sh all updated.

rsync_emby_failover User Script superseded:
  Emby dirty sync was already in HOST1_CRITICAL_SYNC_SHARES — it now runs inside
  critical_sync_maintenance.sh every 30min alongside auth sync and partnership check.
  Section in User Script Plug-in README marked for deletion from plugin.

transcode_management.sh: */3 → */7:
  transcode_management.sh, transcode_manager.sh, transcode_cleanup.sh headers,
  Transcodes README/manual, Orchestrators README, User Script Plug-in README,
  user_script_plug-in.sh all updated.

Docker_Essentials/README-Docker_Essentials.md

@@ -197,7 +197,7 @@ array start. Silent when everything is correct. Notifies when it has to create s
 
 ### 🧹  Downloader Hygiene — `downloaders_reset.sh`
 
-Maintenance reset for all download clients (slskd, SABnzbd, qBittorrent) every 15
+Maintenance reset for all download clients (slskd, SABnzbd, qBittorrent) every 30
 minutes. Clears stuck searches, dead transfers, failed imports, and stale queue entries
 that download clients accumulate but never clean up themselves. Never touches active
 or in-progress downloads.
@@ -233,7 +233,7 @@ full coordination model between all four watchdogs.
 | `docker_update_remaining.sh` | Image update + prune for all containers not in managed lists | End of weekly maintenance window |
 | `docker_network_connect.sh` | Network existence + container connection enforcement | Every array start |
 | `docker_container_stop.sh` | Ordered container shutdown — graceful then forced | Called by `array_stopping.sh` |
-| `downloaders_reset.sh` | Download client hygiene — slskd / SABnzbd / qBittorrent | Every 15min via `critical_sync_maintenance.sh` |
+| `downloaders_reset.sh` | Download client hygiene — slskd / SABnzbd / qBittorrent | Every 30min via `critical_sync_maintenance.sh` |
 
 > `watchdog_skip_list_manager.sh` — manual recovery tool for the skip list. Lives in `Tools/` because it's an operator utility, not a lifecycle script.
 
@@ -262,7 +262,7 @@ Weekly maintenance window (2:30am Sunday):
         ├── docker_update.sh --remainder ─ update containers not in managed lists
         └── docker_update_remaining.sh ── prune dangling images
 
-Critical maintenance window (every 15min):
+Critical maintenance window (every 30min):
     critical_sync_maintenance.sh
         └── downloaders_reset.sh ──────── clear stuck downloads / stale queue entries
 

Docker_Essentials/downloaders_reset.sh

@@ -9,7 +9,7 @@
 # state that download clients generate but never clean up themselves — stuck
 # searches, dead transfers, failed imports, stale queue entries, completed history.
 #
-# Called every 15 minutes by critical_sync_maintenance.sh via
+# Called every 30 minutes by critical_sync_maintenance.sh via
 # CRITICAL_MAINTENANCE_SCRIPTS. Can also be run manually for ad hoc cleanup.
 # If a downloader is not configured for this host, that section skips cleanly.
 #
@@ -137,7 +137,7 @@ if [[ "$EUID" -ne 0 ]]; then
     exit 1
 fi
 
-# Lock first — wait mode since this runs every 15min and previous may still be finishing
+# Lock first — wait mode since this runs every 30min and previous may still be finishing
 acquire_lock "wait"
 
 # detect_hosts() sets MY_ID and aliases all HOST*_SLSKD_*, HOST*_SABNZBD_*, HOST*_QBIT_* vars