Show when a watchdog cycle last completed

Without it the page renders zeros, all-clear pills and green dots when the
orchestrator has stopped entirely — its healthiest appearance describing a
machine with no watchdogs, against a header promising absence is never drawn as
an all-clear. The heartbeat already existed; overdue is measured against the
cron schedule rather than an assumed fifteen minutes.

Plugin/unraid/include/watchdog.php

@@ -84,6 +84,25 @@ function vv_wd_installed_containers(): array {
     return array_values(array_filter(array_map('trim', $out), fn($n) => $n !== ''));
 }
 
+// How many minutes are supposed to pass between watchdog cycles.
+//
+// Parsed from varaverk.cron, which the scheduler regenerates at array start and is the only place
+// the answer exists — the interval is a schedule, not a conf key. Reading it rather than assuming
+// 15 means that changing the schedule also moves the point at which the page calls a cycle
+// overdue, instead of leaving a constant here to drift out of agreement with reality.
+//
+// Falls back to 15 when the cron is missing or the entry is written in a form this does not
+// recognise. A wrong-but-sane interval produces a slightly early or late warning; refusing to
+// answer would remove the liveness check altogether, which is the failure being fixed.
+function vv_wd_cycle_interval_min(): int {
+    $cron = @file_get_contents('/boot/config/plugins/varaverk/varaverk.cron') ?: '';
+    foreach (explode("\n", $cron) as $line) {
+        if (!str_contains($line, 'watchdog_orchestrator')) continue;
+        if (preg_match('#^\s*\*/(\d+)\s#', $line, $m)) return max(1, (int)$m[1]);
+    }
+    return 15;
+}
+
 // ── Conf array parser (bash arrays) ──────────────────────────────────────────
 
 function vv_wd_bash_array(string $raw, string $varname): array {
@@ -272,6 +291,9 @@ function vv_wd_local_states(string $restartLogPath): array {
         'ctr_strikes'    => $strikes,
         'skiplist'       => vv_wd_parse_skiplist($skipRaw),
         'sys_strikes'    => $sysStrikes,
+        // The heartbeat, not a strike — see VV_WD_SYS_BOOKKEEPING. stability_watchdog.sh writes it
+        // last in the chain, so a fresh value means a whole cycle completed rather than started.
+        'last_cycle'     => (int)($sys['watchdog_cycle'] ?? 0),
         'reboots'        => vv_wd_parse_reboot_log($rebootRaw),
         'restarts'       => vv_wd_parse_restart_log($restartRaw),
         'storage_wd'     => vv_wd_parse_storage_state($storRaw) + [
@@ -391,6 +413,7 @@ function vv_wd_remote_data(string $ip, string $sshKey, string $restartLogPath):
             'ctr_strikes'  => $strikes,
             'skiplist'     => vv_wd_parse_skiplist($skipRaw),
             'sys_strikes'  => $sysStrikes,
+            'last_cycle'   => (int)($sys['watchdog_cycle'] ?? 0),
             'reboots'      => vv_wd_parse_reboot_log($rebootRaw),
             'restarts'     => vv_wd_parse_restart_log($restartRaw),
             'storage_wd'   => vv_wd_parse_storage_state($storRaw) + [
@@ -465,6 +488,10 @@ function vv_wd_all(): array {
         // than omit a member of SYSTEM_WATCHDOG_SCRIPTS entirely and let its absence read as fine.
         'fallback_on'    => vv_wd_scalar($masterRaw, 'FALLBACK_ENABLED')   === 'true',
         'conf_sync_on'   => vv_wd_scalar($masterRaw, 'CONF_SYNC_ENABLED')  !== 'false',
+        // How often a cycle is supposed to happen, so "overdue" is measured against the schedule
+        // in force rather than a number written here. Read from the cron because that is where
+        // the answer lives — there is no conf key for it.
+        'cycle_min'      => vv_wd_cycle_interval_min(),
     ];
 
     // SSH key from current host conf