Closes#3
## Summary
- enforce `currentPeriodEnd` as a hard access boundary for generation requests
- transition elapsed `active` and `past_due` subscriptions to `expired` during runtime reads
- stop showing active-cycle quota for non-active subscriptions and document the current lifecycle behavior
- add DB tests for post-expiry generation rejection and expired account-view normalization
## Testing
- built `infra/docker/web.Dockerfile`
- ran `pnpm --filter @nproxy/db test` inside the built container
- verified `@nproxy/db build` and `@nproxy/web build` during the image build
Co-authored-by: sirily <sirily@git.shararam.party>
Reviewed-on: #19
sirily
624c5809b6