feat(backup): enhance backup job with S3 upload handling and notifications

- Introduced a new notification class, BackupSuccessWithS3Warning, to alert users when local backups succeed but S3 uploads fail.
- Updated DatabaseBackupJob to track local backup success and handle S3 upload errors, improving error reporting and user notifications.
- Modified ScheduledDatabaseBackupExecution model to include a new s3_uploaded boolean field for tracking S3 upload status.
- Adjusted views and validation logic to reflect changes in backup execution status and S3 handling.
- Added tests to ensure the new s3_uploaded column is correctly implemented and validated.

database/migrations/2025_10_07_120723_add_s3_uploaded_to_scheduled_database_backup_executions_table.php

@@ -0,0 +1,28 @@
+<?php
+
+use Illuminate\Database\Migrations\Migration;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Support\Facades\Schema;
+
+return new class extends Migration
+{
+    /**
+     * Run the migrations.
+     */
+    public function up(): void
+    {
+        Schema::table('scheduled_database_backup_executions', function (Blueprint $table) {
+            $table->boolean('s3_uploaded')->nullable()->after('filename');
+        });
+    }
+
+    /**
+     * Reverse the migrations.
+     */
+    public function down(): void
+    {
+        Schema::table('scheduled_database_backup_executions', function (Blueprint $table) {
+            $table->dropColumn('s3_uploaded');
+        });
+    }
+};