feat: add PubSub event broadcasting for job lifecycle

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

lib/towerops/job_monitoring/events.ex

@@ -0,0 +1,37 @@
+defmodule Towerops.JobMonitoring.Events do
+  @moduledoc """
+  PubSub event broadcasting for job lifecycle events.
+  """
+
+  @topic "job:lifecycle"
+
+  @doc """
+  Broadcasts a job lifecycle event to PubSub.
+
+  ## Events
+  - `:started` - Job began executing
+  - `:completed` - Job finished successfully
+  - `:failed` - Job failed with error
+
+  ## Metadata
+  Optional map with additional context:
+  - `duration`: Execution time in seconds
+  - `error`: Error message/reason
+  - `items_collected`: Number of items discovered/polled
+  """
+  @spec broadcast_job_event(Oban.Job.t(), atom(), map()) :: :ok | {:error, term()}
+  def broadcast_job_event(%Oban.Job{} = job, event, metadata \\ %{}) do
+    Phoenix.PubSub.broadcast(
+      Towerops.PubSub,
+      @topic,
+      %{
+        job_id: job.id,
+        worker: job.worker,
+        device_id: get_in(job.args, ["device_id"]),
+        event: event,
+        metadata: metadata,
+        timestamp: DateTime.utc_now()
+      }
+    )
+  end
+end

test/towerops/job_monitoring/events_test.exs

@@ -0,0 +1,28 @@
+defmodule Towerops.JobMonitoring.EventsTest do
+  use Towerops.DataCase, async: true
+
+  alias Towerops.JobMonitoring.Events
+
+  describe "broadcast_job_event/3" do
+    test "broadcasts job lifecycle event to PubSub" do
+      Phoenix.PubSub.subscribe(Towerops.PubSub, "job:lifecycle")
+
+      job = %Oban.Job{
+        id: 123,
+        worker: "Towerops.Workers.DevicePollerWorker",
+        args: %{"device_id" => 456}
+      }
+
+      Events.broadcast_job_event(job, :started, %{})
+
+      assert_receive %{
+        job_id: 123,
+        worker: "Towerops.Workers.DevicePollerWorker",
+        device_id: 456,
+        event: :started,
+        metadata: %{},
+        timestamp: %DateTime{}
+      }
+    end
+  end
+end