refactor(lib): move songToTrack + pure server-scope helpers to lib/media; split trackServerScope

songToTrack (the canonical Subsonic-song -> Track mapper) and the pure
server-scope helpers (activeServerProfileId, stampTrackServerId/s,
isMultiServerQueue, profileIdFromQueueRef) operate only on the lib/media model +
authStore + server-key utils -- no playback-store read. Move them to lib/media so
the ~58 app-wide consumers (cover, context menus, sharing, lucky-mix, library
browse, pages, hooks) depend on lib, not on the playback feature.

trackServerScope is split: the store-reading queue helpers (queueItemRefAt,
filterQueueRefs*, activeServerQueueTrackIds) stay in
features/playback/utils/playback/trackServerScope and build on the pure lib half.

With Track/QueueItemRef (prior commit), songToTrack and shuffleArray now in lib,
the media-domain model is fully out of features/playback. The remaining
playerStoreTypes imports are PlayerState only (the store shape). tsc 0, lint 0,
full suite 2353/2353, build OK.

src/features/search/components/LiveSearch.tsx

@@ -1,6 +1,6 @@
 import { subscribeLibrarySyncIdle, subscribeLibrarySyncProgress } from '@/lib/api/library';
 import type { SearchResults, SubsonicArtist } from '@/lib/api/subsonicTypes';
-import { songToTrack } from '@/features/playback/utils/playback/songToTrack';
+import { songToTrack } from '@/lib/media/songToTrack';
 import {
   LIVE_SEARCH_DEBOUNCE_NETWORK_MS,
   LIVE_SEARCH_DEBOUNCE_RACE_MS,

src/features/search/components/MobileSearchOverlay.tsx

@@ -1,6 +1,6 @@
 import { search } from '@/lib/api/subsonicSearch';
 import type { SearchResults, SubsonicArtist } from '@/lib/api/subsonicTypes';
-import { songToTrack } from '@/features/playback/utils/playback/songToTrack';
+import { songToTrack } from '@/lib/media/songToTrack';
 import { useLiveSearchScopeStore } from '@/store/liveSearchScopeStore';
 import React, { useState, useEffect, useRef, useCallback, useMemo } from 'react';
 import { createPortal } from 'react-dom';

src/features/search/components/ShareSearchResults.tsx

@@ -4,7 +4,7 @@ import { useTranslation } from 'react-i18next';
 import type { TFunction } from 'i18next';
 import type { SubsonicArtist } from '@/lib/api/subsonicTypes';
 import type { ServerProfile } from '@/store/authStoreTypes';
-import { songToTrack } from '@/features/playback/utils/playback/songToTrack';
+import { songToTrack } from '@/lib/media/songToTrack';
 import { activateShareSearchServer } from '@/utils/share/enqueueShareSearchPayload';
 import { sharePayloadTotal, type ShareSearchMatch } from '@/utils/share/shareSearch';
 import type { ShareSearchPreviewState } from '@/features/search/hooks/useShareSearchPreview';