B2B-9 · Temporal exclusivity: private→commons reopen job (NGO plan)

Part of the B2B epic (Bloco 2). After X months of exclusivity, a private check returns to the commons.

## What
- [ ] Bootstrap `ScheduleModule` — `@nestjs/schedule` is in `package.json:99` but **unused anywhere**
- [ ] `openDate`/`license`/`exclusivityEndsAt` fields on `claim-review`
- [ ] `@Cron` job flipping visibility private→public + "reopen" state transition (`src/machines/reviewTask/`)

## Notes
- Commons model makes this cheap: personalities are global, so "opening" a claim is just flipping the check's namespace/visibility — no entity merging.
- **Source dedup on reopen**: the private source may collide with an existing public one — the job must dedup against the public namespace (covered by the compound-index design in B2B-3), not blind-insert.
- Open decision: what triggers the exclusivity clock (publication? assignment?).

**Effort:** ~1–1.5 SP · **Depends on:** B2B-1..4 (isolation), B2B-3 (dedup design)