Propagate new fallback model to all remaining script references

All FALLBACK_${MY_ID}_COVERS_${REMOTE_ID}_TIER* references updated to
FALLBACK_${REMOTE_ID}_TIER* across fallback_test.sh, partnership_manager.sh,
docker_update.sh, mesh_monitor.sh, and monitor.php. mesh_monitor.sh drops
the inner covering-host loop — tier data now lives in the covered host's own
conf so no cross-host scan is needed. monitor.php reads from the covered
host's conf file rather than the local host's.

Docker_Essentials/docker_update.sh

@@ -219,7 +219,7 @@ if [[ "$REMAINDER_MODE" == true ]]; then
     # Updating them here risks version divergence: if remote's writeback after handback
     # encounters data written by a newer version, it may not handle it correctly.
     for _tier in 1 2 3 4; do
-        _tier_var="FALLBACK_${MY_ID}_COVERS_${REMOTE_ID}_TIER${_tier}"
+        _tier_var="FALLBACK_${REMOTE_ID}_TIER${_tier}"
         eval "_tier_arr=(\"\${${_tier_var}[@]:-}\")" 2>/dev/null
         for _c in "${_tier_arr[@]}"; do
             [[ -n "$_c" ]] && _exclude["$_c"]=1