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rsync_emby_failover User Script superseded: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.

Configurations/master.conf

@@ -40,7 +40,7 @@
 #   MONTHLY MAINTENANCE             Uptime-triggered heavy tasks — ZFS scrub, SMART tests (monthly_maintenance.sh)
 #   DAILY SYNC MAINTENANCE          Job list + media shares (daily_sync_maintenance.sh)
 #   WEEKLY SYNC MAINTENANCE         Job list + sync shares + update toggles (weekly_sync_maintenance.sh)
-#   CRITICAL SYNC MAINTENANCE       15-minute jobs + sync shares + partnership check (critical_sync_maintenance.sh)
+#   CRITICAL SYNC MAINTENANCE       30-minute jobs + sync shares + partnership check (critical_sync_maintenance.sh)
 #
 #   ── RSYNC ──────────────────────────────────────────────────────────────────────────────────
 #   RSYNC ENABLE/DISABLE            Two-tier toggle system — global gate + per-orchestrator
@@ -154,7 +154,7 @@
 #   /boot/config/partnership_HOST2.db ← HOST2 writes only
 #   Propagated via SSH — no rsync needed
 #
-# critical_sync_maintenance.sh runs --check every 15min:
+# critical_sync_maintenance.sh runs --check every 30min:
 #   Reads both state files via SSH
 #   Detects offboard requests → finalises from owner side
 #   Increments offline counter → auto-offboards after threshold
@@ -330,15 +330,15 @@
     MONTHLY_LAST_RUN_FILE="/boot/config/monthly_maintenance_last_run.db"
 
 # ━━━ Critical Sync Maintenance ━━━
-# critical_sync_maintenance.sh runs every 15 minutes.
+# critical_sync_maintenance.sh runs every 30 minutes.
 # Order: CRITICAL_MAINTENANCE_SCRIPTS (jobs) → CRITICAL_SYNC_SHARES (rsync) → partnership --check
 # partnership --check always runs last regardless of rsync gate.
 # Comment out entries to disable without removing.
     CRITICAL_MAINTENANCE_SCRIPTS=(
-        "Docker_Essentials/downloaders_reset.sh"        # clear stuck download states every 15min
+        "Docker_Essentials/downloaders_reset.sh"        # clear stuck download states every 30min
     )
 
-# Shares synced every 15 minutes — defined per host in host*.conf.
+# Shares synced every 30 minutes — defined per host in host*.conf.
 # HOST1_CRITICAL_SYNC_SHARES / HOST2_CRITICAL_SYNC_SHARES
 # Format: "/path/to/share" or "/path/to/share|profile-name"
 # Order matters — Critical-Data first (auth stack), then Emby dirty sync.
@@ -442,7 +442,7 @@
 #   RSYNC_ENABLED=true           ← rsync works, individual scripts run fine
 #   DAILY_RSYNC_ENABLED=false    ← skip daily HDD syncs during rebuild
 #   WEEKLY_RSYNC_ENABLED=true    ← Emby + Critical-Data still sync (NVMe)
-#   CRITICAL_RSYNC_ENABLED=true  ← 15min auth stack sync still runs
+#   CRITICAL_RSYNC_ENABLED=true  ← 30min auth stack sync still runs
 #   FALLBACK_RSYNC_ENABLED=true  ← handback writeback still works
 #   → Run individual: bash Rsync/rsync.sh /mnt/user/Movies
 #   → When ready: DAILY_RSYNC_ENABLED=true
@@ -493,14 +493,14 @@
 #   critical-data     — auth stack — full stop both sides, Authelia delayed start
 #                       called by weekly_sync_maintenance.sh — full clean sync weekly
 #   critical-fallback — dirty sync — auth stays running both sides, WAL excluded
-#                       called by critical_sync_maintenance.sh every 15min
+#                       called by critical_sync_maintenance.sh every 30min
 #   host1-appdata     — HOST1 server-specific appdata — defined in host1.conf
 #   host2-appdata     — HOST2 server-specific appdata — defined in host2.conf
 #   important-data    — NextCloud + Postgres — NextCloud delayed start after Postgres
 #   emby              — weekly clean sync — both Emby stopped, full mirror
 #                       called by weekly_sync_maintenance.sh only — do NOT schedule separately
 #   emby-fallback     — dirty sync — Emby stays running, WAL excluded
-#                       called by critical_sync_maintenance.sh every 15min
+#                       called by critical_sync_maintenance.sh every 30min
 
     declare -A PROFILE_RSYNC_OPTS=(
         [arrs_stack]="-av --info=progress2 --human-readable --bwlimit=$BW_LIMIT --delete --inplace"
@@ -632,7 +632,7 @@
 # ==============================================================================================
 
 # ━━━ Downloaders Reset ━━━
-# Runs every 15 minutes via CRITICAL_MAINTENANCE_SCRIPTS.
+# Runs every 30 minutes via CRITICAL_MAINTENANCE_SCRIPTS.
 # Clears stuck states, purges old history, prepares each download client for a clean cycle.
 # Per-host URLs and API keys live in host*.conf.
     DOWNLOADER_RETENTION_DAYS=7     # days — purge history older than this