Add USB policy improvements and emprestimos details modal

- Add cron job to cleanup stale pending USB policies every 30 min
- Add cleanupStalePendingPolicies mutation to usbPolicy.ts
- Add USB policy fields to machines listByTenant query
- Display USB status chip in device details and bulk control modal
- Add details modal for emprestimos with all loan information
- Add observacoesDevolucao field to preserve original observations
- Fix status text size in details modal title

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

convex/schema.ts

@@ -801,6 +801,7 @@ export default defineSchema({
     dataDevolucao: v.optional(v.number()),
     status: v.string(),
     observacoes: v.optional(v.string()),
+    observacoesDevolucao: v.optional(v.string()),
     multaDiaria: v.optional(v.number()),
     multaCalculada: v.optional(v.number()),
     createdBy: v.id("users"),