feat(track-list): show Album by default, and search smart playlists

H-15: the default columns were track, artist and duration, so a library
manager with duplicate detection could not tell its own duplicate
fixtures apart by eye. Album is a default now, in Go and in the
frontend fallback — both, because a fresh install persists the Go list
and the UI renders the TS one until the config arrives.

It does not deliver the finding's stated benefit, and that is worth
recording: the three `Tideline / Aurora Fields / 00:06` rows are
duplicates of the same album, so they read identically with an Album
column too. What tells them apart is the duplicate-detection feature or
a file path column, not this. Album is still the right default for
every other row in the list.

smart-playlist-details joins search-store's scope map. Checked before
adding, as asked: it reads searchCtrl.term in getVisibleTracks and
prints the term in the page, so the header box was disabled and
unlabelled on a view that filters as you type — the fix is a scope
entry, not a disabled state with a reason.

frontend/src/components/track-list/columns.ts

@@ -249,9 +249,16 @@ export const CORE_SEARCH_COLUMN_IDS: string[] = [
     'album',
 ];
 
-/** Default column IDs matching the original hardcoded layout. */
+/**
+ * Default column IDs. Album is in them (H-15): without it, the three
+ * `Tideline / Aurora Fields / 00:06` rows in this app's own fixture
+ * library are indistinguishable, in an app that has duplicate
+ * detection. Must match `tracklist.DefaultColumns` in Go, which is what
+ * a fresh install actually persists.
+ */
 export const DEFAULT_COLUMN_IDS: string[] = [
     'trackName',
     'artistName',
+    'album',
     'trackLength',
 ];