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.

System_Essentials/conf_sync.sh

@@ -81,7 +81,7 @@ if [[ "${CONF_SYNC_ENABLED:-true}" == false ]]; then
     exit 0
 fi
 
-CACHE_DIR="/tmp/.cache/vv/d"
+CACHE_DIR="$CONF_RAM_CACHE_DIR"
 MY_CONF="$SCRIPTS_DIR/Configurations/${MY_ID,,}.conf"
 SSH_TIMEOUT=10