chore(playback): remove Preload Next Track setting (#1007)

* chore(playback): remove Preload Next Track setting

The configurable next-track RAM preload duplicated hot cache and is
obsolete now that ranged streaming starts playback sooner. Gapless and
crossfade still use the internal audio_preload backup when hot cache is off.

* docs: add CHANGELOG entry for Preload Next Track removal (PR #1007)

src/locales/en/settings.ts

@@ -334,7 +334,7 @@ export const settings = {
   analyticsStrategyAdvancedDesc: 'More aggressive background scan. Once finished, you get BPM for every track plus instant loudness + waveform loads.',
   analyticsStrategyPriorityTitle: 'Analysis priority (always enforced)',
   analyticsStrategyPriorityHigh: '1 — Currently playing: download + analyze first (playback bytes, loudness backfill, or HTTP when needed).',
-  analyticsStrategyPriorityMiddle: '2 — Up next: the next ~5 queue tracks, preload next, and hot-cache neighbours — analyze from cached/downloaded bytes when possible; HTTP backfill only on miss.',
+  analyticsStrategyPriorityMiddle: '2 — Up next: the next ~5 queue tracks and hot-cache neighbours — analyze from cached/downloaded bytes when possible; HTTP backfill only on miss.',
   analyticsStrategyPriorityLow: '3 — Library batch (Aggressive only): automatic background queue at the tail; refilled by watermark (~3× workers) without waiting for an empty queue.',
   analyticsStrategyServerLabel: 'Server',
   analyticsStrategyProgressLabel: 'Analysis progress:',
@@ -577,15 +577,7 @@ export const settings = {
   trackPreviewLocation_favorites: 'In favorites',
   trackPreviewLocation_artist: 'In artist top tracks',
   trackPreviewLocation_randomMix: 'In Random Mix',
-  preloadMode: 'Preload Next Track',
-  preloadModeDesc: 'When to start buffering the next track in the queue',
   nextTrackBufferingTitle: 'Buffering',
-  preloadHotCacheMutualExclusive: 'Preload and Hot Cache serve the same purpose — only one can be active at a time. Enabling one will automatically disable the other.',
-  preloadOff: 'Off',
-  preloadBalanced: 'Balanced (30 s before end)',
-  preloadEarly: 'Early (after 5 s of playback)',
-  preloadCustom: 'Custom',
-  preloadCustomSeconds: 'Seconds before end: {{n}}',
   infiniteQueue: 'Infinite Queue',
   infiniteQueueDesc: 'Automatically append random tracks when the queue runs out',
   experimental: 'Experimental',