[Maybe] Campaign open/bounce/click tracking via webhooks

[0xheartcode]

Overview

Add delivery event tracking (opens, clicks, bounces) for email campaigns. Currently campaigns are fire-and-forget — we send but don't know what happens after.

What's needed

• campaign_events table — per-recipient event log (campaign_id, subscriber_email, event_type, timestamp)
• Webhook endpoints — POST /api/webhooks/ahasend and POST /api/webhooks/resend with signature verification
• Provider-side config — register webhook URLs on AhaSend/Resend dashboards
• Stats rollup — aggregate into campaign-level open rate, bounce rate, click rate
• UI — per-campaign stats view (maybe a detail page or expandable row)

Notes

• Both AhaSend and Resend support webhook events, but payload formats and signature verification differ
• Requires a publicly accessible URL (won't work on localhost without a tunnel)
• The existing campaigns table already has recipient_count — this extends it with delivery metrics
• Could be a simple count columns approach or a full normalized events table depending on how granular we want

Status

Undecided — parking this for now. May implement later depending on need.

[0xheartcode]

🤔