fix: auto-dismiss agent offline insights when agent reconnects

lib/towerops/agents.ex

@@ -195,9 +195,32 @@ defmodule Towerops.Agents do
         _ -> [last_seen_at: now, last_ip: ip_address]
       end
 
-    AgentToken
-    |> where([t], t.id == ^agent_token_id)
-    |> Repo.update_all(set: updates)
+    result =
+      AgentToken
+      |> where([t], t.id == ^agent_token_id)
+      |> Repo.update_all(set: updates)
+
+    # Auto-dismiss agent offline insights when agent comes back online
+    dismiss_agent_offline_insights(agent_token_id)
+
+    result
+  end
+
+  defp dismiss_agent_offline_insights(agent_token_id) do
+    alias Towerops.Preseem.Insight
+
+    now = DateTime.truncate(DateTime.utc_now(), :second)
+
+    {count, _} =
+      Insight
+      |> where(agent_token_id: ^agent_token_id, type: "agent_offline", status: "active")
+      |> Repo.update_all(set: [status: "dismissed", dismissed_at: now])
+
+    if count > 0 do
+      Logger.info("Auto-dismissed #{count} agent offline insight(s) for agent #{agent_token_id}")
+    end
+
+    :ok
   end
 
   @doc """