rename: fix remaining failover refs in fallback.sh, fallback_test.sh, array_started.sh, user_script_plug-in.sh

Fallback/fallback.sh

@@ -370,7 +370,7 @@ _abort_fallback_containers() {
 # ==============================================================================================
 # All docker commands wrapped in DOCKER_TIMEOUT.
 # All SSH docker commands wrapped in SSH_TIMEOUT.
-# Verification after start — failover is critical, confirm containers came up.
+# Verification after start — fallback is critical, confirm containers came up.
 
 # Start a container locally and verify it came up
 local_start() {
@@ -996,7 +996,7 @@ while [[ "$FALLBACK_RUNNING" == true ]]; do
                 "Fallback" "warning"
 
         else
-            # Still in failover — check tier escalation
+            # Still in FALLBACK state — check tier escalation
             state_set handback_strikes "0"
 
             TIER2_DELAY=$(get_tier2_delay)
@@ -1092,7 +1092,7 @@ while [[ "$FALLBACK_RUNNING" == true ]]; do
 
             if [[ "$REMOTE_UP" == true ]]; then
                 warn "Remote up, internet up — transitioning through FALLBACK for handback"
-                # Was in failover before DARK — route through FALLBACK state for handback
+                # Was in FALLBACK state before DARK — route through FALLBACK state for handback
                 state_set state "FALLBACK"
                 state_set handback_strikes "0"
             else