Provision {space}@rspace.online forwarding aliases that route to
opted-in members' personal emails. Admins/mods opted in by default;
regular members can opt in via PUT /api/spaces/:slug/email-forwarding/me.
New: space-alias-service.ts, schema tables, 8 DB functions, 6 API routes.
Hooks: rinbox onSpaceCreate/Delete, spaces.ts member lifecycle, startup migration.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
