Webhook event for opt-in submissions + API access to consent records

Currently the platform stores opt-in consent data behind the scenes, but there's no way for agencies to access it programmatically. For US agencies operating under TCPA rules, having a real-time and exportable consent trail is becoming a hard requirement.

Two requests:

1. Add a new webhook event (e.g. "optin-created") that fires when a customer submits the campaign opt-in page. The payload should include: contact name, phone/email, timestamp, IP address, and the consent text they agreed to. This would let agencies automatically store consent records on their side without needing to raise a support ticket each time.

2. As a simpler first step, include consent record fields (opted-in timestamp, IP, consent language) in the API response when listing campaign contacts.

This would be a strong differentiator for EMR — most competing platforms don't offer webhook-level consent tracking, and US agencies are increasingly looking for this as TCPA enforcement tightens. Having it built in would give EMR a compliance edge that competitors like Birdeye and Podium don't currently offer.