refactor: documents

Signed-off-by: Sebastian Krupinski <krupinski01@gmail.com>

core/lib/Logger/FileLogger.php

@@ -40,11 +40,18 @@ class FileLogger implements LoggerInterface
 
     public function log($level, $message, array $context = []): void
     {
-        $timestamp = $this->formatTimestamp();
-        $interpolated = $this->interpolate((string)$message, $context);
+        // Extract tenant id injected by TenantAwareLogger; default to 'system'.
+        $tenantId = isset($context['__tenant']) && is_string($context['__tenant'])
+            ? $context['__tenant']
+            : 'system';
+        unset($context['__tenant']);
+
+        $timestamp    = $this->formatTimestamp();
+        $interpolated = $this->interpolate((string) $message, $context);
         $payload = [
-            'time' => $timestamp,
-            'level' => strtolower((string)$level),
+            'time'    => $timestamp,
+            'level'   => strtolower((string) $level),
+            'tenant'  => $tenantId,
             'channel' => $this->channel,
             'message' => $interpolated,
             'context' => $this->sanitizeContext($context),
@@ -53,11 +60,12 @@ class FileLogger implements LoggerInterface
         if ($json === false) {
             // Fallback stringify if encoding fails (should be rare)
             $json = json_encode([
-                'time' => $timestamp,
-                'level' => strtolower((string)$level),
-                'channel' => $this->channel,
-                'message' => $interpolated,
-                'context_error' => 'failed to encode context: '.json_last_error_msg(),
+                'time'          => $timestamp,
+                'level'         => strtolower((string) $level),
+                'tenant'        => $tenantId,
+                'channel'       => $this->channel,
+                'message'       => $interpolated,
+                'context_error' => 'failed to encode context: ' . json_last_error_msg(),
             ], JSON_UNESCAPED_SLASHES | JSON_UNESCAPED_UNICODE) ?: '{"error":"logging failure"}';
         }
         $this->write($json);