feat(scheduler): live running indicators for cron-triggered jobs

Add api/status.php — reads all scheduled jobs' stat files and returns a
{id: status} map. The scheduler page polls it every 3s and lights up the
dot on any job whose stat shows status=running, clearing it when done.

Replace single vvRunningId with vvRunningSet (Set) so multiple jobs can
show as running simultaneously. vvSetDot/vvClearDot handle per-job dots
and the header dot for the active job. Remove stale-count detection from
vvFetchRight — status poll is now the single source of truth.

Plugin/usr/local/emhttp/plugins/varaverk/api/status.php

@@ -0,0 +1,19 @@
+<?php
+// Returns current run status for all scheduled jobs.
+// Used by the scheduler page to light up running indicators without user interaction.
+header('Content-Type: application/json');
+require_once dirname(__DIR__) . '/include/scheduler.php';
+
+$schedule = vv_schedule_load();
+$result   = [];
+foreach ($schedule as $id => $entry) {
+    $statFile = vv_job_stat_path($id);
+    if (!file_exists($statFile)) continue;
+    $stat   = json_decode(@file_get_contents($statFile) ?: '{}', true) ?: [];
+    $status = $stat['status'] ?? 'unknown';
+    if ($status === 'running' && !empty($stat['pid']) && !file_exists("/proc/{$stat['pid']}")) {
+        $status = 'error';
+    }
+    $result[$id] = $status;
+}
+echo json_encode($result);