fix(convex): corrigir memory leak com .collect() sem limite e adicionar otimizacoes

Problema: Convex backend consumindo 16GB+ de RAM causando OOM kills

Correcoes aplicadas:
- Substituido todos os .collect() por .take(LIMIT) em 27+ arquivos
- Adicionado indice by_usbPolicyStatus para otimizar query de maquinas
- Corrigido N+1 problem em alerts.ts usando Map lookup
- Corrigido full table scan em usbPolicy.ts
- Corrigido subscription leaks no frontend (tickets-view, use-ticket-categories)
- Atualizado versao do Convex backend para precompiled-2025-12-04-cc6af4c

Arquivos principais modificados:
- convex/*.ts - limites em todas as queries .collect()
- convex/schema.ts - novo indice by_usbPolicyStatus
- convex/alerts.ts - N+1 fix com Map
- convex/usbPolicy.ts - uso do novo indice
- src/components/tickets/tickets-view.tsx - skip condicional
- src/hooks/use-ticket-categories.ts - skip condicional

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

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

convex/deviceFields.ts

@@ -64,7 +64,7 @@ export const list = query({
       .query("deviceFields")
       .withIndex("by_tenant_order", (q) => q.eq("tenantId", tenantId))
 
-    const fields = await fieldsQuery.collect()
+    const fields = await fieldsQuery.take(100)
     return fields
       .filter((field) => matchesCompany(field.companyId, companyId, true))
       .filter((field) => matchesScope(field.scope, scope))
@@ -96,7 +96,7 @@ export const listForTenant = query({
     const fields = await ctx.db
       .query("deviceFields")
       .withIndex("by_tenant_order", (q) => q.eq("tenantId", tenantId))
-      .collect()
+      .take(100)
 
     return fields
       .filter((field) => matchesCompany(field.companyId, companyId, false))
@@ -153,7 +153,7 @@ export const create = mutation({
     const existing = await ctx.db
       .query("deviceFields")
       .withIndex("by_tenant_order", (q) => q.eq("tenantId", args.tenantId))
-      .collect()
+      .take(100)
     const maxOrder = existing.reduce((acc, item) => Math.max(acc, item.order ?? 0), 0)
     const now = Date.now()