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rsync_emby_failover User Script superseded: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.

Transcodes/README-Transcoding.md

@@ -49,7 +49,7 @@ it at mount time. Both protections together prevent this permanently.
 **lsof Per File on a Live TV System**  
 Early cleanup called `lsof filename` per file to check if anything had it open. On a busy
 Live TV night with 5 simultaneous streams, the ramdisk contains thousands of HLS segment
-files — thousands of subprocess calls every 3 minutes.  
+files — thousands of subprocess calls every 7 minutes.  
 Fix: lsof called once per location to build a complete open-file map. All subsequent
 checks are O(1) lookups against that map.
 
@@ -82,7 +82,7 @@ unRAID_Essentials/
 Orchestrators/
   transcode_management.sh ──── cleanup first ──► transcode_cleanup.sh
                            ──── then manager ──► transcode_manager.sh
-                           (every 3 minutes — order non-negotiable)
+                           (every 7 minutes — order non-negotiable)
 
 Monitors/
   weekly_health_digest.sh ◄─── reads ──────────── TRANSCODE_DAILY_LOG
@@ -121,7 +121,7 @@ Emby starts, reads transcode path from config
     All new sessions write to: /mnt/ram-transcode → /mnt/ramdisk_transcodes/
 
 
-Every 3 minutes (transcode_management.sh):
+Every 7 minutes (transcode_management.sh):
     │
     ├─ transcode_cleanup.sh
     │    Remove files older than TRANSCODE_MAX_AGE, not open by any process