Plugin: common.php library, watchdog expansion, monitor + scheduler improvements

PHP architecture:
- Extract common.php from monitor.php — shared system functions (vv_system_info,
  vv_memory_breakdown, vv_remote_hosts_stats, disk/GPU/UPS/network/docker/parity, etc.)
  now live in one place; monitor.php and watchdog.php both require common.php
- Add unraid_api.php as explicit include (was implicit via config.php chain)
- confform.php: add missing require_once config.php (implicit dep made explicit)
- Delete orphaned pages/docs.php and pages/config.php (absorbed into scheduler)

Watchdog page:
- Add Storage watchdog card (growth + log strikes, baseline age, suppress ceilings)
- Add Network watchdog card (NPM strikes, DDNS domain/container, NPM URL)
- One host per row layout — all 5 watchdog cards equally spaced via inner grid
- Watchdog now uses Unraid API for local system stats; remote nodes with API key
  but no SSH get system info from vv_remote_hosts_stats() with api_only flag
- SSH bundle: /proc/meminfo passed as raw section instead of awk-parsed header
  fields — fixes RAM showing 0 on remote hosts where awk quoting was unreliable
- vv_wd_local_system() rewritten as thin wrapper over vv_system_info() + vv_memory_breakdown()

Monitor page:
- Watchdog card: add stability strikes, storage watchdog strikes, network NPM status,
  live system stats (rootfs/log/tmp %, RAM free, load, CPU temp, zombies, NIC, sshd)
- Row height: switch from max-height on cards to minmax(0, calc(...)) on grid track —
  all cards in a row now fill to the tallest card's height correctly (fixes Pools card
  being shorter than neighbours)

Scheduler page:
- Add Tools section above Custom Scripts — lists Tools/*.sh with run/dry-run/cron/log
- vv_tools_scripts() function in scheduler.php include

Tools:
- Add docker_prune_images.sh — removes dangling Docker images; --dry-run and --status modes

Plugin/unraid/include/scheduler.php

@@ -230,6 +230,26 @@ function vv_script_description(string $path): string {
     return $first;
 }
 
+function vv_tools_scripts(): array {
+    $dir      = SCRIPTS_DIR . '/Tools';
+    $schedule = vv_schedule_load();
+    $scripts  = [];
+    foreach (glob("$dir/*.sh") ?: [] as $path) {
+        $rel       = 'Tools/' . basename($path);
+        $entry     = $schedule[$rel] ?? [];
+        $scripts[] = [
+            'id'          => $rel,
+            'label'       => vv_pretty_label(basename($path, '.sh')),
+            'desc'        => vv_script_description($path),
+            'enabled'     => (bool)($entry['enabled'] ?? false),
+            'cron'        => $entry['cron'] ?? '',
+            'log_enabled' => (bool)($entry['log_enabled'] ?? false),
+        ];
+    }
+    usort($scripts, fn($a, $b) => strcmp($a['label'], $b['label']));
+    return $scripts;
+}
+
 function vv_custom_scripts(): array {
     $dir      = SCRIPTS_DIR . '/Custom';
     $schedule = vv_schedule_load();