v0.1.4 `followup/email_links` filter exposes URLs discovered in the final follow-up body for PRO engagement tracking.
v0.1.3 `followup/should_send` filter before a follow-up claims an order, so PRO can defer sends to a chosen hour or weekday.
v0.1.2 Fire `followup/email_sent` after a follow-up is accepted by wp_mail for PRO send reporting. Document the `{coupon}` placeholder for Followup Pro coupon blocks.
v0.1.1 Add the `followup/sequence_steps` extension filter so add-ons can append custom post-purchase email steps.
v0.1.0 Initial release: thank-you and review request follow-up emails with per-type enable, trigger status, delay and templates; idempotent daily sender.