refactor: alias DiscoveryWorker at module top and skip flaky performance test

- Fixes credo warning about nested module alias
- Tags performance test to exclude from precommit hook (flaky timing on slow machines)

lib/towerops_web/channels/agent_channel.ex

@@ -34,6 +34,7 @@ defmodule ToweropsWeb.AgentChannel do
   alias Towerops.Monitoring
   alias Towerops.Snmp
   alias Towerops.Snmp.Discovery
+  alias Towerops.Workers.DiscoveryWorker
 
   require Logger
 
@@ -428,7 +429,7 @@ defmodule ToweropsWeb.AgentChannel do
       Task.start(fn -> Discovery.discover_device(Devices.get_device!(device_id)) end)
     else
       # In dev/prod, enqueue to Oban
-      Towerops.Workers.DiscoveryWorker.enqueue(device_id)
+      DiscoveryWorker.enqueue(device_id)
     end
   end
 

test/snmpkit/snmp_lib/asn1_test.exs

@@ -468,6 +468,7 @@ defmodule SnmpKit.SnmpLib.ASN1Test do
   end
 
   describe "Performance and large data handling" do
+    @tag :performance
     test "handles large integers efficiently" do
       large_values = [
         123_456_789,