feat(admission): add scheduled group access

design/us-017-group-access.md

@@ -19,6 +19,8 @@ As an administrator, I want to organize registered users into access groups, so
 - [x] The `everyone` group remains created with Minecraft access disabled.
 - [x] Administrators can create groups with access disabled by default and move users between groups.
 - [x] Administrators can enable or disable Minecraft admission for each group.
+- [x] Disabled Minecraft admission always denies group members; enabled admission may additionally be restricted by recurring UTC windows.
+- [x] Groups without windows retain unrestricted scheduling, and groups with windows admit logins only during an active window.
 - [x] Admission follows only the user's effective group; default and explicit-group access are never combined.
 - [x] Administrators can delete non-default groups, returning affected users to `everyone`.
 - [x] The protected default group cannot be deleted.
@@ -40,6 +42,7 @@ As an administrator, I want to organize registered users into access groups, so
 - [`packages/database/drizzle/0002_simple_queen_noir.sql`](../packages/database/drizzle/0002_simple_queen_noir.sql)
 - [`packages/database/drizzle/0003_smiling_silver_samurai.sql`](../packages/database/drizzle/0003_smiling_silver_samurai.sql)
 - [`packages/database/drizzle/0004_zippy_silver_centurion.sql`](../packages/database/drizzle/0004_zippy_silver_centurion.sql)
+- [`packages/database/drizzle/0005_young_vertigo.sql`](../packages/database/drizzle/0005_young_vertigo.sql)
 - [`apps/web/src/app/admin/(console)/groups/page.tsx`](../apps/web/src/app/admin/%28console%29/groups/page.tsx)
 - [`apps/web/src/app/admin/(console)/groups/[groupId]/page.tsx`](../apps/web/src/app/admin/%28console%29/groups/%5BgroupId%5D/page.tsx)
 - [`apps/web/src/app/api/velocity/access/route.ts`](../apps/web/src/app/api/velocity/access/route.ts)