fix: rename playlist tracks -> items

schema/playlist_cache.sql

@@ -11,8 +11,8 @@ CREATE TABLE playlists (
   name TEXT NOT NULL,
   primary_color TEXT,
   snapshot_id TEXT NOT NULL,
-  tracks_href TEXT,
-  tracks_total INTEGER
+  items_href TEXT,
+  items_total INTEGER
 );
 
 CREATE TABLE playlist_images (
@@ -33,8 +33,8 @@ CREATE TABLE tracks (
   duration_ms INTEGER NOT NULL
 );
 
--- Order of tracks in a playlist (matches playlist.tracks.items[] order).
--- track_id NULL when the API returns a removed track (wrapper with track: null).
+-- Order of tracks in a playlist (matches playlist.items.items[] order).
+-- track_id NULL when the API returns a removed entry (wrapper with item: null).
 CREATE TABLE playlist_tracks (
   playlist_id TEXT NOT NULL REFERENCES playlists (id) ON DELETE CASCADE,
   position INTEGER NOT NULL,