Cache the watchdog payload, and stop reading trailing comments as conf values

The tab collected over SSH on every 30s poll — 8.3s a load with HOST2 down.
vv_parse_conf_scalar() captured to end of line, so a commented toggle parsed as
"true   # HOST2 back online": every threshold read right because (int) stops at
the first non-digit, and 38 booleans read wrong. The Fallback tab has been
showing failover disabled while it was on.

Plugin/unraid/pages/watchdog.php

@@ -270,6 +270,17 @@ function _systemCard(node, cfg) {
                  : sys.load1 > sys.cores * cfg.rw_load_soft ? '#ffb74d'
                  : '#4caf50';
 
+  // The fourth member of SYSTEM_WATCHDOG_SCRIPTS, and the only one with nothing to show: it keeps
+  // the persistent backup of the partner's conf current, and writes no state until it does. Drawn
+  // as its gate rather than left off the card, because a chain member that is simply missing from
+  // the page reads as one that is fine — the same reason an unreachable node here says so instead
+  // of rendering healthy. Names the switch, so "why is it off" does not need a hunt through conf.
+  const confCacheHtml = !cfg.fallback_on
+    ? '<span style="color:#555;">off — FALLBACK_ENABLED</span>'
+    : !cfg.conf_sync_on
+      ? '<span style="color:#7a6a20;">off — CONF_SYNC_ENABLED</span>'
+      : '<span style="color:#4caf50;">active</span>';
+
   const apiOnly   = sys.api_only === true;
   const daemonDot = sys.daemon_ok === null ? '#555' : sys.daemon_ok ? '#4caf50' : '#ef5350';
   const daemonTxt = sys.daemon_ok === null ? '—' : sys.daemon_ok ? 'daemon ok' : 'daemon err';
@@ -302,6 +313,7 @@ function _systemCard(node, cfg) {
     <div style="height:5px"></div>` : ''}
     ${_row('Uptime', sys.uptime ? _dur(sys.uptime) : '—')}
     ${_row('Docker', `<span style="color:${daemonDot}">${daemonTxt}</span>`)}
+    ${_row('Conf cache', confCacheHtml)}
     ${!apiOnly ? (sys.oom_count > 0 ? _row('OOM kills', `<span style="color:#ef5350">${sys.oom_count}</span>`) : _row('OOM kills', '<span style="color:#333">0</span>')) : ''}
     ${apiOnly ? `<div style="font-size:10px;color:#333;margin-top:6px;">Watchdog state unavailable — SSH not configured</div>` : ''}
   </div>`;