Respect the configured webhook_model table when storing webhooks

[freekmurze]

Context

This grew out of #253. The issue claimed storeWebhook() ignores the configured webhook_model because of self::create(...). That specific claim is incorrect: self::create() is a forwarding static call, and Eloquent's Model::__callStatic() uses new static, so the model is created against the configured class regardless.

However, while verifying that, I found a real self-vs-static bug introduced with the attachments column (#249):

if (Schema::hasColumn((new self())->getTable(), 'attachments')) {

new self() always builds a base WebhookCall, so for a custom webhook_model mapped to a different table, the attachments-column check probes the base table instead of the configured model's table. A custom model whose table lacks the attachments column (while the default webhook_calls table has it) then tries to insert an attachments column that doesn't exist, and the write fails.

Changes

• Use static:: / new static() throughout storeWebhook() and its static helpers, so late static binding resolves to the configured model (matching the existing static::where(...) in prunable()).
• Add a regression test that stores through a custom-table model whose table has no attachments column while the default table does. It fails on main (SQL error on insert) and passes with this change.

Testing

• vendor/bin/pest → 37 passed (was 36).
• vendor/bin/phpstan analyse → no errors (verified in the CI environment: PHP 8.3 / Laravel 13 / Symfony 7).