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.

Monitors/cert_monitor.sh

@@ -159,43 +159,24 @@ fi
 check_cert() {
     local domain="$1"
     local port="${2:-443}"
-    _CERT_DAYS=""
-    _CERT_EXPIRY=""
 
-    local expiry_str
-    expiry_str=$(echo | timeout "$CERT_TIMEOUT" openssl s_client \
-        -connect "${domain}:${port}" \
-        -servername "$domain" \
-        2>/dev/null | openssl x509 -noout -enddate 2>/dev/null | cut -d= -f2)
-
-    if [[ -z "$expiry_str" ]]; then
-        error "$ICON_CERT $domain — could not retrieve certificate (unreachable or no TLS)"
+    if ! check_cert_expiry "$domain" "$port" "$CERT_TIMEOUT"; then
+        if [[ -n "$_CERT_EXPIRY_RAW" ]]; then
+            error "$ICON_CERT $domain — could not parse expiry date: $_CERT_EXPIRY_RAW"
+        else
+            error "$ICON_CERT $domain — could not retrieve certificate (unreachable or no TLS)"
+        fi
         return 3
     fi
 
-    local expiry_epoch
-    expiry_epoch=$(date -d "$expiry_str" +%s 2>/dev/null)
-
-    if [[ -z "$expiry_epoch" ]]; then
-        error "$ICON_CERT $domain — could not parse expiry date: $expiry_str"
-        return 3
-    fi
-
-    local now days_remaining expiry_display
-    now=$(date +%s)
-    days_remaining=$(( (expiry_epoch - now) / 86400 ))
-    expiry_display=$(date -d "$expiry_str" '+%Y-%m-%d' 2>/dev/null)
-    _CERT_DAYS=$days_remaining
-    _CERT_EXPIRY=$expiry_display
-
-    if [[ "$days_remaining" -le "$CERT_CRIT_DAYS" ]]; then
-        error "$ICON_CERT $domain — CRITICAL: ${days_remaining} days remaining (expires $expiry_display)"
+    if [[ "$_CERT_DAYS" -le "$CERT_CRIT_DAYS" ]]; then
+        error "$ICON_CERT $domain — CRITICAL: ${_CERT_DAYS} days remaining (expires $_CERT_EXPIRY)"
         return 2
-    elif [[ "$days_remaining" -le "$CERT_WARN_DAYS" ]]; then
-        warn "$ICON_CERT $domain — WARNING: ${days_remaining} days remaining (expires $expiry_display)"
+    elif [[ "$_CERT_DAYS" -le "$CERT_WARN_DAYS" ]]; then
+        warn "$ICON_CERT $domain — WARNING: ${_CERT_DAYS} days remaining (expires $_CERT_EXPIRY)"
         return 1
     else
-        log "$ICON_CERT $domain — OK: ${days_remaining} days remaining (expires $expiry_display)"
+        log "$ICON_CERT $domain — OK: ${_CERT_DAYS} days remaining (expires $_CERT_EXPIRY)"
         return 0
     fi
 }
@@ -285,7 +266,7 @@ fi
 echo "━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━"
 
 # ── Write JSON status cache ───────────────────────────────────────────────────
-_CERT_CACHE_FILE="$SCRIPTS_DIR/State_Files/cert_status.json"
+_CERT_CACHE_FILE="$STATE_DIR/cert_status.json"
 {
     printf '{"checked_at":%d,"host":"%s","warn_days":%d,"crit_days":%d,"dry_run":%s,"domains":[\n' \
         "$(date +%s)" "$MY_ID" "$CERT_WARN_DAYS" "$CERT_CRIT_DAYS" \