Fix dead/incorrect vars and consolidate duplicated logic into common.sh

Codebase-wide audit pass: fixed real bugs (SSH hangs missing BatchMode,
local-outside-function no-ops, variable name collisions, a truncated
ratio calc, wrong state-dir path, DARK vs NO_INTERNET drift, and more),
then pulled logic that was duplicated across multiple scripts — arr
cleanup safety gates, docker restart ordering, container maintenance
stop/restart, watchdog state-file helpers, partnership role resolution,
cert expiry checks, remote node discovery, and TMDB discovery scoring —
into common.sh so each now has a single implementation.

Fallback/fallback.sh

@@ -1000,12 +1000,19 @@ while [[ "$FALLBACK_RUNNING" == true ]]; do
             fi
 
         elif [[ "$INTERNET_UP" == false ]]; then
-            # Lost internet during fallback — enter DARK
+            # Lost internet during fallback — enter DARK — same actions as NO_INTERNET
             echo ""
             echo "━━━ $ICON_NET Entering DARK — $(date '+%Y-%m-%d %H:%M:%S') ━━━"
             warn "Lost internet during fallback — entering DARK state"
             state_set state "DARK"
             local_ddns_stop
+
+            # Stop containers configured to stop on internet loss
+            read -r -a stop_on_no_net <<< "$(get_stop_on_no_net)"
+            for container in "${stop_on_no_net[@]}"; do
+                [[ -n "$container" ]] && local_stop "$container"
+            done
+
             notify "DARK state on $(hostname) — lost internet during fallback" \
                 "Fallback" "warning"