Replaces the v0.3.0 / v0.7.0 allowed_emails admission gate with an
admin-grant flow (roadmap item #6, SPEC §6.1 / §6.2 / §14.1 / §17).
Any valid email can sign in via OTC; a fresh user lands in
permission_state='pending' with a captured first/last/why profile,
and an admin grant flips them to 'granted' before write endpoints
accept them. Grandfathered users pass through the migration with
the column default 'granted' so existing contributors are unaffected.
The allowed_emails table stays in the schema as a fast-path bypass
pending v0.9.0's admin user-management page (item #7).
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Ben Stull
ca8ba69acb