Monitor: 1-second CPU/mem/net updates via fast endpoint

Split slow cached monitor endpoint from the live stats. monitor_fast.php
reads /proc/stat, /proc/meminfo, ZFS arcstats, and /proc/net/dev directly
— no cache wrapper, 87ms response. Docker/vm/swap pulled from last full
cache so mem card stays complete. Full monitor poll stays at 2s for
everything else (GPU, containers, storage, etc).

Plugin/unraid/api/monitor_fast.php

@@ -0,0 +1,48 @@
+<?php
+header('Content-Type: application/json');
+require_once dirname(__DIR__) . '/include/config.php';
+require_once dirname(__DIR__) . '/include/common.php';
+
+// Pull slow fields (docker/vm/top_procs/swap) from last full cache — stale is fine,
+// these don't change on a per-second basis. 600s window so the card stays populated
+// even if the full cache writer is temporarily behind.
+$_full      = vv_cache_read('monitor', 600);
+$_dockerKb  = $_full['mem']['docker_kb']      ?? 0;
+$_vmKb      = $_full['mem']['vm_kb']          ?? 0;
+$_topProcs  = $_full['mem']['top_procs']      ?? [];
+$_swapTotal = $_full['mem']['swap_total_kb']  ?? 0;
+$_swapUsed  = $_full['mem']['swap_used_kb']   ?? 0;
+
+// Fast memory: /proc/meminfo + ZFS ARC (no docker stats, no GQL)
+$_memRaw = [];
+foreach (file('/proc/meminfo') ?: [] as $_l) {
+    if (preg_match('/^(\w+):\s+(\d+)/', $_l, $_m)) $_memRaw[$_m[1]] = (int)$_m[2];
+}
+$_totalKb = $_memRaw['MemTotal']    ?? 0;
+$_freeKb  = $_memRaw['MemAvailable'] ?? 0;
+$_arcKb   = 0;
+foreach (@file('/proc/spl/kstat/zfs/arcstats') ?: [] as $_l) {
+    if (preg_match('/^size\s+\d+\s+(\d+)/', $_l, $_m)) { $_arcKb = (int)($_m[1] / 1024); break; }
+}
+if (!$_swapTotal) {
+    $_swapTotal = $_memRaw['SwapTotal'] ?? 0;
+    $_swapUsed  = max(0, ($_memRaw['SwapTotal'] ?? 0) - ($_memRaw['SwapFree'] ?? 0));
+}
+
+echo json_encode([
+    'cpu' => vv_cpu_per_core(),
+    'mem' => [
+        'total_kb'      => $_totalKb,
+        'free_kb'       => $_freeKb,
+        'used_kb'       => max(0, $_totalKb - $_freeKb),
+        'arc_kb'        => $_arcKb,
+        'docker_kb'     => $_dockerKb,
+        'vm_kb'         => $_vmKb,
+        'system_kb'     => max(0, $_totalKb - $_freeKb - $_arcKb - $_dockerKb - $_vmKb),
+        'swap_total_kb' => $_swapTotal,
+        'swap_used_kb'  => $_swapUsed,
+        'top_procs'     => $_topProcs,
+    ],
+    'net' => vv_network_stats(),
+    'ts'  => time(),
+]);