feat: add site size and total disk to filesystem health check

Reports total_disk_mb and site_size_mb (images, media, tmp, cache, logs).
Shows in Infrastructure table on Grafana dashboard.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/Extension/MokoWaaS.php

@@ -1286,12 +1286,55 @@ class MokoWaaS extends CMSPlugin
 			$status = 'degraded';
 		}
 
+		// Total disk and site size
+		$totalBytes = @disk_total_space(JPATH_ROOT);
+		$totalMb    = $totalBytes !== false
+			? round($totalBytes / 1048576)
+			: null;
+
+		// Site directory size (quick estimate via common dirs)
+		$siteMb = null;
+
+		try
+		{
+			$siteSize = 0;
+
+			foreach (['images', 'media', 'tmp', 'cache',
+				'administrator/logs', 'administrator/cache'] as $dir)
+			{
+				$path = JPATH_ROOT . '/' . $dir;
+
+				if (is_dir($path))
+				{
+					$iter = new \RecursiveIteratorIterator(
+						new \RecursiveDirectoryIterator(
+							$path,
+							\FilesystemIterator::SKIP_DOTS
+						)
+					);
+
+					foreach ($iter as $file)
+					{
+						$siteSize += $file->getSize();
+					}
+				}
+			}
+
+			$siteMb = round($siteSize / 1048576);
+		}
+		catch (\Exception $e)
+		{
+			// Ignore — siteMb stays null
+		}
+
 		return [
 			'status'         => $status,
 			'tmp_writable'   => $tmpWritable,
 			'log_writable'   => $logWritable,
 			'cache_writable' => $cacheWritable,
 			'free_disk_mb'   => $freeMb,
+			'total_disk_mb'  => $totalMb,
+			'site_size_mb'   => $siteMb,
 		];
 	}