refactor(models): add fillable attributes for database configuration options

Add explicit fillable attributes to Service and all Standalone* database models
for new configuration options: public_port_timeout, enable_ssl, ssl_mode,
is_log_drain_enabled, is_include_timestamps, and custom_docker_run_options.

Add tests to MassAssignmentProtectionTest to verify these attributes are
properly protected by mass assignment protection across all relevant models.

app/Models/StandaloneKeydb.php

@@ -37,6 +37,9 @@ class StandaloneKeydb extends BaseModel
         'last_restart_at',
         'last_restart_type',
         'last_online_at',
+        'public_port_timeout',
+        'enable_ssl',
+        'custom_docker_run_options',
     ];
 
     protected $appends = ['internal_db_url', 'external_db_url', 'server_status'];