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/usbPolicy.ts

@@ -196,12 +196,13 @@ export const listUsbPolicyEvents = query({
   },
   handler: async (ctx, args) => {
     const limit = args.limit ?? 10
+    const maxFetch = 1000 // Limite maximo de eventos a buscar
 
     let events = await ctx.db
       .query("usbPolicyEvents")
       .withIndex("by_machine_created", (q) => q.eq("machineId", args.machineId))
       .order("desc")
-      .collect()
+      .take(maxFetch)
 
     // Aplica filtro de cursor (paginacao)
     if (args.cursor !== undefined) {
@@ -313,13 +314,11 @@ export const cleanupStalePendingPolicies = mutation({
     const cutoff = now - thresholdMs
 
     // Buscar maquinas com status PENDING e appliedAt antigo
-    const allMachines = await ctx.db.query("machines").collect()
-    const staleMachines = allMachines.filter(
-      (m) =>
-        m.usbPolicyStatus === "PENDING" &&
-        m.usbPolicyAppliedAt !== undefined &&
-        m.usbPolicyAppliedAt < cutoff
-    )
+    const staleMachines = await ctx.db
+      .query("machines")
+      .withIndex("by_usbPolicyStatus", (q) => q.eq("usbPolicyStatus", "PENDING"))
+      .filter((q) => q.lt(q.field("usbPolicyAppliedAt"), cutoff))
+      .take(1000)
 
     let cleaned = 0
     for (const machine of staleMachines) {
@@ -346,6 +345,6 @@ export const cleanupStalePendingPolicies = mutation({
       cleaned++
     }
 
-    return { cleaned, checked: allMachines.length }
+    return { cleaned, checked: staleMachines.length }
   },
 })