Openspec Proposal Creation

This generates structured change proposals using spec-driven development, scaffolding out proposal.md for rationale, tasks.md for implementation steps, and spec-delta.md with formal ADDED/MODIFIED/REMOVED requirements in EARS format. It walks through an eight-step workflow from reviewing existing specs to validation, making sure you don't skip the grep checks or forget error scenarios. Useful when you're planning features before coding and want the discipline of writing requirements first. The progressive disclosure is smart, keeping the main guide under 500 lines while linking to deeper references on EARS syntax and validation patterns when you need them.