Connectors: record outbound request deliveries the way WebhookAction does

Found while planning barakocms.com as a barakoCMS-backed site.

`WebhookAction` writes a `WebhookDelivery` row for every attempt, with the response and timing, and `/api/webhook-deliveries` serves them. `RequestAction` sends through `ConnectorSender`, which returns a status and elapsed time and records nothing beyond the workflow run.

## Why this matters

The two actions do the same thing, an outbound HTTP call from a workflow, with different observability. "Did the request fire, and what came back" is answerable for webhooks and not for connector requests. When a request action fails intermittently, the workflow run says the step failed and the response body is gone.

The retention service (`WebhookDeliveryRetentionService`) already exists, so the storage and cleanup side is solved.

## What to change

Record outbound connector requests the same way, subject to the same retention, with the credential redacted the way `WithoutSecret` does for parameters.

Start by comparing WebhookAction and its WebhookDelivery records with RequestAction and ConnectorSender, which returns the status and elapsed time. Read WebhookDeliveryRetentionService and WithoutSecret to understand the existing retention and credential-redaction conventions. Done means connector outbound attempts retain the relevant response and timing information under the same cleanup rules without exposing credentials.

Written by the indexing model from the issue text.