doc audit — fix stale watchdog vars, fallback_state_reset, add monthly_maintenance and mesh_monitor sections

- Tools/Manual-Tools.md: fallback_state_reset.sh marked not yet built; manual
  workaround added; TOC entry updated; failover→fallback rename throughout
- Watchdogs/Manual-Watchdogs.md: System Watchdog config block updated — remove
  pre-split vars (MEM_WARN_GB, MEM_SHUTDOWN_GB, MEM_GB, MEM_RECOVER_GB,
  SYS_WATCHDOG_MEM_SHUTDOWN_EXCLUDED, SYS_WATCHDOG_REQUIRED_CONTAINERS);
  add SYS_WATCHDOG_MEM_GB (reboot trigger only); fix state file path names
  (watchdog_state.db → container_watchdog_state.db,
  sys_watchdog_state.db → system_watchdog_state.db)
- Orchestrators/README-Orchestrators.md: add monthly_maintenance.sh section
  with two-gate model, configuration reference, and usage examples
- Monitors/README-Monitors.md: add mesh_monitor.sh to both tables and diagram
- Monitors/Manual-Monitors.md: add mesh_monitor.sh section
- README-User_Script_Plug-in.md, Rsync/README-Rsync.md, Rsync/Manual-Rsync.md,
  README.md: emby-failover → emby-fallback (missed from prior batch)

Rsync/Manual-Rsync.md

@@ -342,19 +342,19 @@ PROFILES["emby_EXCLUDE_DIRS"]=(
     "transcodes/" "logs/" "crash*" "cache/"
 )
 
-# ── emby-failover ─────────────────────────────────────────────────────────────
+# ── emby-fallback ─────────────────────────────────────────────────────────────
 # Every 30 minutes, Emby STAYS RUNNING — dirty sync of critical state only
-PROFILES["emby-failover_CRITICAL_CONTAINER_NAMES"]=()   # nothing stops
-PROFILES["emby-failover_EXCLUDE_DIRS"]=(
+PROFILES["emby-fallback_CRITICAL_CONTAINER_NAMES"]=()   # nothing stops
+PROFILES["emby-fallback_EXCLUDE_DIRS"]=(
     "*.wal" "*.shm"                            # unsafe mid-write
     "transcodes/" "logs/" "crash*" "cache/"
 )
-PROFILES["emby-failover_REMOTE_RESTART_CONTAINERS"]=("Emby")
+PROFILES["emby-fallback_REMOTE_RESTART_CONTAINERS"]=("Emby")
 ```
 
 ### Two Emby Profiles — Why Both Exist
 
-**emby-failover** (every 30 minutes, Emby stays running):
+**emby-fallback** (every 30 minutes, Emby stays running):
 - Syncs: users.db, library.db, authentication.db, config/
 - Skips: \*.wal, \*.shm, transcodes/, logs/, cache/
 - Why: WAL files are written while Emby runs — copying them would produce a corrupt database on HOST2
@@ -366,7 +366,7 @@ PROFILES["emby-failover_REMOTE_RESTART_CONTAINERS"]=("Emby")
 - Why: WAL is checkpointed on clean shutdown — safe to copy everything
 - Result: HOST2 gets a gold-standard Emby state once per week
 
-The two profiles work together. emby-failover keeps HOST2 current for immediate failover.
+The two profiles work together. emby-fallback keeps HOST2 current for immediate failover.
 emby gives HOST2 full fidelity once per week. Neither alone is sufficient.
 
 ---
@@ -448,7 +448,7 @@ Watchdogs (resource, docker, system, stability) run separately via watchdog_orch
 # Every 30 minutes — Emby dirty sync:
 */30 * * * *
 bash /mnt/user/appdata/unraid_scripts/Rsync/rsync.sh \
-    /mnt/user/Media_Server/Emby --profile=emby-failover
+    /mnt/user/Media_Server/Emby --profile=emby-fallback
 
 # Every 6 hours — failed import + stalled download recovery:
 0 */6 * * *
@@ -731,5 +731,5 @@ name doesn't match any profile key, or when testing a specific profile.
 
 ```bash
 rsync.sh /mnt/user/appdata-Failover/Critical-Data --profile=critical-data
-rsync.sh /mnt/user/Media_Server/Emby --profile=emby-failover
+rsync.sh /mnt/user/Media_Server/Emby --profile=emby-fallback
 ```