feat(audit): comprehensive logging — auth events, severity, source, IP

Audit log was previously silent on authentication and on background
work. This wires:

- Login (success + failed) and logout via a wrapper around better-auth's
  [...all] handler. Failed logins are severity 'warning' and carry the
  attempted email so brute-force attempts surface in the inspector.
- New severity (info|warning|error|critical) and source (user|auth|
  system|webhook|cron|job) columns on audit_logs. permission_denied
  defaults to 'warning', hard_delete to 'critical'.
- Webhook delivery success/failure/DLQ/retry now write audit rows
  alongside the webhook_deliveries detail table.
- IP address is now visible as a column in the inspector (was already
  captured at the helper level).
- Audit UI: severity badges per row, severity + source dropdowns, IP
  column, expanded action filter covering hard-delete, webhook events,
  job/cron events.

Migration 0044 adds the two columns + their port-scoped indexes.
1175/1175 vitest passing.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/lib/services/webhooks.service.ts

@@ -330,7 +330,7 @@ export async function redeliverWebhookDelivery(
   void createAuditLog({
     userId: meta.userId,
     portId,
-    action: 'send',
+    action: 'webhook_retried',
     entityType: 'webhook_delivery',
     entityId: next!.id,
     metadata: { redeliveredFrom: deliveryId, originalStatus: source.status },