complete story 8.8 with qa tests

app/Observers/TimelineUpdateObserver.php

@@ -0,0 +1,25 @@
+<?php
+
+namespace App\Observers;
+
+use App\Enums\TimelineStatus;
+use App\Mail\TimelineUpdateEmail;
+use App\Models\TimelineUpdate;
+use Illuminate\Support\Facades\Mail;
+
+class TimelineUpdateObserver
+{
+    public function created(TimelineUpdate $update): void
+    {
+        // Only send for active timelines
+        if ($update->timeline->status !== TimelineStatus::Active) {
+            return;
+        }
+
+        $client = $update->timeline->user;
+
+        Mail::to($client->email)->queue(
+            new TimelineUpdateEmail($update)
+        );
+    }
+}