Player: seek hover tooltip on the Now Playing progress bar

The mockup had a seek tooltip (timestamp tracks the cursor over the progress
bar) but it was never ported to the real player. Added it: mousemove computes
the hovered fraction -> formatTime(duration*frac), positions the tip, shows on
hover / hides on leave. Guarded when no duration. Frontend-only; JS + CSS clean.

webui/index.html

@@ -7068,6 +7068,7 @@
                                 <div class="np-progress-fill" id="np-progress-fill"></div>
                             </div>
                             <input type="range" class="np-progress-bar" id="np-progress-bar" min="0" max="100" value="0" step="0.1">
+                            <div class="np-seek-tip" id="np-seek-tip">0:00</div>
                         </div>
                         <div class="np-time-display">
                             <span class="np-current-time" id="np-current-time">0:00</span>

webui/static/media-player.js

@@ -1537,6 +1537,23 @@ function initExpandedPlayer() {
     npProgressBar.addEventListener('mousedown', () => { npProgressBar.dataset.seeking = 'true'; });
     npProgressBar.addEventListener('mouseup', () => { delete npProgressBar.dataset.seeking; });
 
+    // Seek hover tooltip — shows the timestamp the cursor is over.
+    const npSeekTip = document.getElementById('np-seek-tip');
+    if (npSeekTip) {
+        npProgressBar.addEventListener('mousemove', (e) => {
+            if (!audioPlayer || !isFinite(audioPlayer.duration) || audioPlayer.duration <= 0) {
+                npSeekTip.classList.remove('visible');
+                return;
+            }
+            const rect = npProgressBar.getBoundingClientRect();
+            const frac = Math.max(0, Math.min(1, (e.clientX - rect.left) / rect.width));
+            npSeekTip.textContent = formatTime(frac * audioPlayer.duration);
+            npSeekTip.style.left = (frac * 100) + '%';
+            npSeekTip.classList.add('visible');
+        });
+        npProgressBar.addEventListener('mouseleave', () => npSeekTip.classList.remove('visible'));
+    }
+
     // Progress bar (touch)
     npProgressBar.addEventListener('touchstart', () => { npProgressBar.dataset.seeking = 'true'; }, { passive: true });
     npProgressBar.addEventListener('touchmove', (e) => {

webui/static/style.css

@@ -48705,6 +48705,16 @@ textarea.enhanced-meta-field-input {
 .np-progress-bar-container:hover .np-progress-fill { box-shadow: 0 0 12px rgba(var(--accent-rgb),0.6) !important; }
 .np-time-display { font-variant-numeric: tabular-nums !important; }
 
+/* Seek hover tooltip — timestamp under the cursor on the progress bar. */
+.np-progress-bar-container { position: relative; }
+.np-seek-tip {
+    position: absolute; bottom: 150%; transform: translateX(-50%);
+    background: #000; color: #fff; font-size: 11px; font-variant-numeric: tabular-nums;
+    padding: 3px 7px; border-radius: 6px; white-space: nowrap; pointer-events: none;
+    opacity: 0; transition: opacity 0.12s ease; box-shadow: 0 4px 12px rgba(0,0,0,0.5); z-index: 5;
+}
+.np-seek-tip.visible { opacity: 1; }
+
 /* ── Transport: dominant gradient play button ── */
 .np-controls-row { gap: 24px !important; }
 .np-btn {