Extract DB queries from MaintenanceLive into context

lib/music_library/maintenance.ex

@@ -0,0 +1,39 @@
+defmodule MusicLibrary.Maintenance do
+  @moduledoc """
+  Context for database maintenance operations and background job monitoring.
+  """
+
+  import Ecto.Query
+
+  alias MusicLibrary.BackgroundRepo
+  alias MusicLibrary.Repo
+
+  @doc """
+  Counts active Oban jobs for the given worker module name.
+
+  Active jobs are those in "available", "scheduled", "executing", or "retryable" states.
+  """
+  def count_active_jobs(worker) do
+    query =
+      from j in Oban.Job,
+        where: j.worker == ^worker,
+        where: j.state in ["available", "scheduled", "executing", "retryable"],
+        select: count(j.id)
+
+    BackgroundRepo.one(query)
+  end
+
+  @doc """
+  Runs VACUUM on the main database.
+  """
+  def vacuum do
+    Repo.vacuum()
+  end
+
+  @doc """
+  Runs PRAGMA optimize on the main database.
+  """
+  def optimize do
+    Repo.optimize()
+  end
+end