feat(ui): rebuild player view to match Studio Reference mockup

Restructures the player tab DOM to actually look like the editorial
mockup, not just inherit new fonts. The previous commit only swapped
tokens & typography on the legacy Spotify-clone layout.

DOM additions (all preserve existing JS-touched IDs):
- Vinyl stage: rotating vinyl wrapping the existing #album-art as a
  circular center label; spins only when state=playing via CSS hook
- SVG tonearm: pivots in/out based on data-playstate
- Kicker line: copper italic mono header above the track title
- Editorial 4-cell metadata grid: State / Source / Elapsed / Length
- Decorative spectrum bars (30, CSS-only animation, paused when idle)
- VU meter cluster: needle visual driven by volume %, alongside the
  preserved volume slider for a11y
- Folio marks: top-left and top-right of the player container

JS hooks (small, additive):
- updatePlaybackState now sets :root[data-playstate] for CSS
- progress tick mirrors timecode into meta-grid cells
- volume update rotates the VU needle
- folio-version mirrors the version label

i18n:
- new keys: player.kicker, player.modes, player.folio_*, meta.*
- added to both en.json and ru.json

Restored: media_server/static/redesign-mockup.html (Studio Reference
visual reference; deleting it in the prior commit was a mistake).

media_server/static/js/player.js

@@ -677,6 +677,12 @@ export function updateUI(status) {
         dom.volumeDisplay.textContent = `${status.volume}%`;
         dom.miniVolumeSlider.value = status.volume;
         dom.miniVolumeDisplay.textContent = `${status.volume}%`;
+        // VU needle: map 0-100 volume to -45deg..+45deg rotation.
+        const needle = document.getElementById('vuNeedle');
+        if (needle) {
+            const deg = -45 + (status.volume / 100) * 90;
+            needle.style.transform = `rotate(${deg}deg)`;
+        }
     }
 
     updateMuteIcon(status.muted);
@@ -700,6 +706,8 @@ export function updateUI(status) {
 
 export function updatePlaybackState(state) {
     setCurrentPlayState(state);
+    // Expose state to CSS so tonearm / vinyl spin can react.
+    document.documentElement.dataset.playstate = state;
     switch(state) {
         case 'playing':
             dom.playbackState.textContent = t('state.playing');
@@ -739,6 +747,8 @@ function updateProgress(position, duration) {
     dom.progressFill.style.width = widthStr;
     dom.currentTime.textContent = currentStr;
     dom.totalTime.textContent = totalStr;
+    if (dom.metaElapsed) dom.metaElapsed.textContent = currentStr;
+    if (dom.metaLength) dom.metaLength.textContent = totalStr;
     dom.progressBar.dataset.duration = duration;
     dom.progressBar.setAttribute('aria-valuenow', posRound);
     dom.progressBar.setAttribute('aria-valuemax', durRound);