Varaverk: FallBack + Watchdog tabs; plugin path restructure to Plugin/unraid/

- FallBack tab: per-node tier inventory + active fallback card with duration, tier, handback strikes, running container status
- Watchdog tab: live system health (RAM bar + thresholds, load, uptime, daemon), docker watchdog strikes + skip list + restart history, stability strikes + reboot log, resource pressure alert card, config inventory (mem limits, required, pause/stop lists)
- Swapped partnership/arrs tab order; FallBack between partnership and watchdog
- Plugin source tree moved from Plugin/usr/local/emhttp/plugins/varaverk/ to Plugin/unraid/
- Deployment/ conf templates added

Plugin/unraid/api/system.php

@@ -0,0 +1,20 @@
+<?php
+header('Content-Type: application/json');
+
+$body  = json_decode(file_get_contents('php://input'), true) ?? [];
+$action = $body['action'] ?? '';
+
+$allowed = ['stop', 'shutdown', 'restart'];
+if (!in_array($action, $allowed, true)) {
+    echo json_encode(['ok' => false, 'error' => 'invalid action']);
+    exit;
+}
+
+$cmd = match($action) {
+    'stop'     => '/usr/local/sbin/mdcmd stop',
+    'shutdown' => '/sbin/shutdown -h now',
+    'restart'  => '/sbin/shutdown -r now',
+};
+
+exec($cmd . ' > /dev/null 2>&1 &');
+echo json_encode(['ok' => true]);