Add infrastructure to persist scrobble tracks to database

Unused for now.

lib/last_fm/track.ex

@@ -20,11 +20,11 @@ defmodule LastFm.Track do
           last_fm_data: map()
         }
 
-  embedded_schema do
+  @primary_key {:scrobbled_at_uts, :integer, autogenerate: false}
+  schema "scrobbled_tracks" do
     field :musicbrainz_id, :string
     field :title, :string
     field :cover_url, :string
-    field :scrobbled_at_uts, :integer
     field :scrobbled_at_label, :string
 
     embeds_one :artist, Artist

priv/repo/migrations/20250530203701_create_scrobbled_tracks.exs

@@ -0,0 +1,16 @@
+defmodule MusicLibrary.Repo.Migrations.CreateScrobbledTracks do
+  use Ecto.Migration
+
+  def change do
+    create table(:scrobbled_tracks, primary_key: false) do
+      add :scrobbled_at_uts, :integer, primary_key: true
+      add :musicbrainz_id, :string
+      add :title, :string
+      add :cover_url, :string
+      add :scrobbled_at_label, :string
+      add :artist, :map
+      add :album, :map
+      add :last_fm_data, :map
+    end
+  end
+end