Ahead of moving webhooks out of the appview and into spindle, port the seven webhook XRPC methods from org.tangled.temp.repo.*Webhook into a dedicated org.tangled.webhook.* namespace: create, update, delete, toggle, list, listDeliveries and retryDelivery. Schemas are carried over verbatim (still keyed on repoDid); only lexicons are defined here, no handlers are wired yet. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>