Add sleep timer to player bar (#1671)

* feat: add sleep timer to player bar

- Add sleep timer button in player bar right controls
- Preset options: End of song, 5/10/15/30/45 min, 1 hr, 2 hrs
- Custom timer with HH:MM:SS input fields
- Timer only counts down while music is playing
- Timer pauses playback when it expires
- End-of-song mode pauses at the next track change
- Uses theme-aware styling (--theme-colors-surface)
- Add sleepTimer/sleepTimerOff icons (LuTimer/LuTimerOff)
- Add i18n strings for sleep timer UI

---------

Co-authored-by: York <york@BonecharMac.local>
Co-authored-by: jeffvli <jeffvictorli@gmail.com>

src/shared/components/icon/icon.tsx

@@ -105,6 +105,8 @@ import {
     LuStepForward,
     LuSun,
     LuTable,
+    LuTimer,
+    LuTimerOff,
     LuTriangleAlert,
     LuUpload,
     LuUser,
@@ -237,6 +239,8 @@ export const AppIcon = {
     share: LuShare2,
     signIn: LuLogIn,
     signOut: LuLogOut,
+    sleepTimer: LuTimer,
+    sleepTimerOff: LuTimerOff,
     sort: LuArrowUpDown,
     sortAsc: LuArrowUpNarrowWide,
     sortDesc: LuArrowDownWideNarrow,