web-player: TypeScript helpers (partial)

Add src/lib/actions/pressable.ts and clickOutside.ts (Svelte actions;
role/tabindex stay static in markup for SSR accessibility, the action
only adds click + Enter/Space) and src/lib/toggle.svelte.ts
(createToggle), used by playlists.svelte.ts and queuePanel.svelte.ts.

format.ts: adds plural(n, one, many); migrates the repo's 15 manual
pluralizations, unifying them to lowercase (visible diff in
Playlists, Home, liked, Explore).

player.svelte.ts: adds toQueueItem, isQueueCurrent, playAllOrToggle,
playShuffled; renames addToQueue -> playNextItem (the old name was
misleading: it inserts next, not at the end). Migrates the 5 places
that repeated the isCurrentQueue/playAll pattern (album, playlist,
liked, mix, Home). Simplifies liked.svelte.ts and recentlyPlayed.ts
with object spread instead of rebuilding every field by hand.

navigation.svelte.ts: adds searchHref (migrates the duplicated
buildHref from TopBar and Explore) and appNavLinks (added; its
adoption in Sidebar/TabsBar is left for a later pass, as noted
there).

menus.svelte.ts: createTrackMenu() replaces the manual context-menu
state (contextMenu + contextMenuStateFor + addToQueue) in Home,
Explore and Mix.

Deliberately left pending: removing tracks.ts's TrackTarget wrapper
and its 8 accessors is deferred — it's the riskiest change in the
plan, touches types across Home/Explore/Mix/menus, and couldn't be
visually verified without Docker this session.

Verified with npm run check/build.

web-player/src/lib/recentlyPlayed.ts

@@ -12,28 +12,14 @@ export function mergeRecentlyPlayed(history: ApiTrackLike[], limit: number): Que
 		const id = String(t.id);
 		if (seen.has(id)) continue;
 		seen.add(id);
-		merged.push({
-			id,
-			title: t.title,
-			artist: t.artist,
-			explicit: t.explicit,
-			ownerUserId: t.ownerUserId,
-			listensCount: t.listensCount
-		});
+		merged.push({ ...t, id });
 	}
 
 	for (const item of toQueueItems(history)) {
 		const id = String(item.id);
 		if (seen.has(id)) continue;
 		seen.add(id);
-		merged.push({
-			id,
-			title: item.title,
-			artist: item.artist,
-			explicit: item.explicit,
-			ownerUserId: item.ownerUserId,
-			listensCount: item.listensCount
-		});
+		merged.push({ ...item, id });
 	}
 
 	return merged.slice(0, limit);