feat(player): polish sleep-timer UI — circular ring + in-button countdown (#272)

Replaces the text-pill schedule badge with a circular SVG progress ring
around the play/pause button. Accent→lavender gradient stroke, counter-
clockwise depletion synced to the armed deadline, subtle accent glow.

While a timer is armed, the Play/Pause icon inside the button is
swapped for a two-line stack: a small Moon (sleep timer) or Sunrise
(delayed start) glyph above the countdown (m:ss / h:mm:ss). The icon
is the mode marker so the ring can stay unified with the rest of the
app's accent palette.

Redesigns the schedule modal with a mood-tinted header (Moon for
"Pause after", Sunrise for "Start after"), soft radial accent glow in
the background, slide-up open animation. Circular glass close-button
scoped to this modal, with hover rotation + focus ring. Custom-minutes
field gains an inline "min" suffix. A live preview line at the bottom
shows when the action fires ("Pauses at 23:47" / "Starts at 23:47"),
updating as the user hovers a preset or types. Chips gain a small
hover lift plus accent-coloured shadow.

Also fixes a pre-existing duplicate-tooltip on the play/pause button:
title= attributes removed alongside the data-tooltip (title violates
the project's "never native tooltips" rule, so both showed at once).

Adds scheduledPauseStartMs / scheduledResumeStartMs to the player
store so the progress ring has a total-duration baseline, set and
cleared alongside the existing deadline fields.

New usePlaybackScheduleRemaining hook wraps the store subscription
and 500 ms tick into a single hook used by all three player views
(PlayerBar / FullscreenPlayer / MobilePlayerView).

i18n: delayPreviewPause / delayPreviewStart keys across all 8 locales.

Co-authored-by: Psychotoxical <dev@psysonic.app>
Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/locales/de.ts

@@ -1129,6 +1129,8 @@ export const deTranslation = {
     delayModalTitle: 'Timer',
     delayPauseSection: 'Pause nach',
     delayStartSection: 'Start nach',
+    delayPreviewPause: 'Pause um',
+    delayPreviewStart: 'Start um',
     delaySchedulePause: 'Pause planen',
     delayScheduleStart: 'Start planen',
     delayCancelPause: 'Pause-Timer abbrechen',