feat: SSE para chat desktop, rate limiting, retry, testes e atualizacao de stack

- Implementa Server-Sent Events (SSE) para chat no desktop com fallback HTTP
- Adiciona rate limiting nas APIs de chat (poll, messages, sessions)
- Adiciona retry com backoff exponencial para mutations
- Cria testes para modulo liveChat (20 testes)
- Corrige testes de SMTP (unit tests para extractEnvelopeAddress)
- Adiciona indice by_status_lastActivity para cron de sessoes inativas
- Atualiza stack: Bun 1.3.4, React 19, recharts 3, noble/hashes 2, etc

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

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

convex/schema.ts

@@ -433,7 +433,8 @@ export default defineSchema({
     .index("by_ticket", ["ticketId"])
     .index("by_machine_status", ["machineId", "status"])
     .index("by_tenant_machine", ["tenantId", "machineId"])
-    .index("by_tenant_status", ["tenantId", "status"]),
+    .index("by_tenant_status", ["tenantId", "status"])
+    .index("by_status_lastActivity", ["status", "lastActivityAt"]),
 
   commentTemplates: defineTable({
     tenantId: v.string(),