fix(metrics): convert container memory samples from bytes to MB

Sentinel stores container used memory in bytes while application and
database charts label the series as megabytes. Convert those samples
before they reach the frontend so the graph is not inflated by ~1024x.

bootstrap/helpers/shared.php

@@ -4724,6 +4724,23 @@ function downsampleLTTB(array $data, int $threshold): array
     return $sampled;
 }
 
+/**
+ * Convert Sentinel container memory samples from bytes to megabytes.
+ *
+ * Sentinel stores container `used` memory in bytes. Application and database
+ * metric charts label the series as megabytes, so the values must be converted
+ * before they are sent to the frontend.
+ *
+ * @param  array<int, array{0: int|float, 1: int|float}>  $metrics
+ * @return array<int, array{0: int, 1: float}>
+ */
+function convertContainerMemoryBytesToMegabytes(array $metrics): array
+{
+    return array_map(static function (array $point): array {
+        return [(int) $point[0], round(((float) $point[1]) / 1024 / 1024, 2)];
+    }, $metrics);
+}
+
 /**
  * Resolve shared environment variable patterns like {{environment.VAR}}, {{project.VAR}}, {{team.VAR}}.
  *