Feature Request: Tier-Level Launch Dates for Offers

I'd love the ability to set a specific open date per pricing tier within an offer. For example, Tier 1 opens October 1, 2026, and Tiers 2 & 3 open January 1, 2027 — all within the same offer.

Right now, the only workarounds are archiving tiers (which breaks upgrade paths for existing members) or using pre-selection parameters in signup links (which requires additional technical setup and doesn't prevent early access). Neither is clean.

A simple "Available from" date field per tier would eliminate the need for these workarounds entirely and make phased launches significantly more manageable — especially for communities with staggered tier rollouts.