feat(plex): player UAT round 2 — mouse-back, +25% UI, seek drag, volume revert

- Mouse/browser Back button now behaves like Backspace/Esc: while a
  menu, the shortcuts sheet, the info overlay or an auto-skip countdown
  is up, Back closes/cancels that (via a history entry) instead of
  dropping straight to the grid; with nothing open it still leaves.
- Whole player UI is 25% larger for lean-back/HTPC legibility, applied
  as transform: scale(1.25) on an 80vw x 80vh root (fills the viewport
  exactly). transform, not zoom — under zoom, event clientX and
  getBoundingClientRect fall into different spaces and the seek/volume/
  hover math breaks; transform keeps them aligned. Skip buttons ride
  this scale (reverted their separate enlargement so they're +25% too).
- Seek bar: drag the head to scrub, not just click-to-jump; the head
  previews the target and the seek commits on release (pointer capture),
  so a long drag doesn't restart the stream on every step.
- Volume bar: dropped the loudness gradient — back to the plain accent
  fill; the 0-100 hover value tooltip stays.
- Harden both bars' pointer-capture calls (try/catch) so a capture
  failure can't abort the click/drag.

frontend/src/components/PlexPlayer.tsx

@@ -35,6 +35,7 @@ import {
 import { api, type PlexMarker } from "../lib/api";
 import { useAccountPersistedObject } from "../lib/storage";
 import { useDismiss } from "../lib/useDismiss";
+import { useBackToClose } from "../lib/history";
 
 // The rich info overlay (poster/cast/ratings) reuses the same component as the card's info page.
 const PlexInfo = lazy(() => import("./PlexInfo"));
@@ -710,6 +711,18 @@ export default function PlexPlayer({ itemId, onClose, queue }: Props) {
     else onClose();
   }, [onClose]);
 
+  // The mouse "back" button (and the browser Back) fire history popstate — which would pop the whole
+  // player subview and drop straight to the grid, even with a panel or an auto-skip countdown up.
+  // While any of those is showing we register a history entry (BackClose below) whose Back handler
+  // runs this: cancel the countdown, else close the topmost panel — matching ⌫ / Esc exactly.
+  const backIntent = useCallback(() => {
+    if (skipProgressRef.current != null) {
+      cancelAutoSkipRef.current();
+      return;
+    }
+    handleBack();
+  }, [handleBack]);
+
   // --- keyboard --------------------------------------------------------------------------------
   useEffect(() => {
     const onKey = (e: KeyboardEvent) => {
@@ -849,6 +862,10 @@ export default function PlexPlayer({ itemId, onClose, queue }: Props) {
 
   // Seekbar hover: a timestamp tooltip that follows the cursor.
   const [hover, setHover] = useState<{ x: number; t: number } | null>(null);
+  // Seekbar scrubbing: the absolute time under the dragging finger. While non-null the head/thumb
+  // preview this position; the real seek fires once on release (avoids restarting the session on
+  // every out-of-buffer step of the drag). A plain click is a down+up at one spot → seeks there.
+  const [scrub, setScrub] = useState<number | null>(null);
   // Volume bar: a 0–100 value tooltip under the cursor (mirrors the seekbar), plus click/drag to set.
   const [volHover, setVolHover] = useState<number | null>(null); // 0..1 under the cursor
   const volBarRef = useRef<HTMLDivElement>(null);
@@ -861,15 +878,29 @@ export default function PlexPlayer({ itemId, onClose, queue }: Props) {
 
   const pct = duration > 0 ? (abs / duration) * 100 : 0;
   const bufPct = duration > 0 ? (seekableEnd / duration) * 100 : 0;
+  // While scrubbing the head follows the finger (preview); otherwise it tracks playback.
+  const headPct = scrub != null && duration > 0 ? (scrub / duration) * 100 : pct;
 
   return (
     <div
       ref={wrapRef}
-      className="fixed inset-0 z-50 bg-black flex items-center justify-center select-none"
+      className="fixed left-0 top-0 z-50 bg-black flex items-center justify-center select-none"
       onMouseMove={wake}
       onClick={wake}
       onWheel={onWheel}
-      style={{ cursor: uiVisible ? "default" : "none" }}
+      // Everything in the player is 25% larger for lean-back / HTPC legibility. Laid out at 80vw×80vh
+      // and scaled ×1.25 from the top-left so it fills the viewport exactly (no overflow, controls stay
+      // on-screen). We use `transform: scale` rather than `zoom` deliberately: under `zoom`, event
+      // clientX stays in CSS pixels while getBoundingClientRect returns zoomed pixels, so the seek/
+      // volume/hover math (clientX − rect.left)/rect.width breaks; with `transform` both are in the same
+      // viewport space, so that ratio stays correct. Skip buttons ride this too → +25% like everything.
+      style={{
+        cursor: uiVisible ? "default" : "none",
+        width: "80vw",
+        height: "80vh",
+        transform: "scale(1.25)",
+        transformOrigin: "top left",
+      }}
     >
       {/* Per-user subtitle appearance (font size / colour / background). ::cue is global, but this
           player owns the only <video> on screen. */}
@@ -909,6 +940,12 @@ export default function PlexPlayer({ itemId, onClose, queue }: Props) {
         </div>
       )}
 
+      {/* While a panel/menu is open or an auto-skip countdown is running, take over the browser/mouse
+          Back button (history popstate) so it closes/cancels that instead of dropping to the grid. */}
+      {(menuOpen || tracksOpen || helpOpen || infoOpen || skipProgress != null) && (
+        <BackClose onBack={backIntent} />
+      )}
+
       {/* Top bar */}
       <div
         className={`absolute top-0 inset-x-0 p-4 bg-gradient-to-b from-black/70 to-transparent transition-opacity ${
@@ -953,7 +990,7 @@ export default function PlexPlayer({ itemId, onClose, queue }: Props) {
       {activeMarker && (
         <button
           onClick={() => doSkip(activeMarker)}
-          className={`absolute right-6 bottom-28 overflow-hidden rounded-lg bg-white/90 px-5 py-2.5 text-[1.09rem] font-medium text-black transition hover:bg-white ${
+          className={`absolute right-6 bottom-28 overflow-hidden rounded-lg bg-white/90 px-4 py-2 text-sm font-medium text-black transition hover:bg-white ${
             uiVisible ? "opacity-100" : "opacity-80"
           }`}
         >
@@ -983,17 +1020,33 @@ export default function PlexPlayer({ itemId, onClose, queue }: Props) {
           uiVisible ? "opacity-100" : "opacity-0 pointer-events-none"
         }`}
       >
-        {/* Seek bar */}
+        {/* Seek bar — click to jump, or drag the head (pointer capture) to scrub; the seek commits on
+            release so a long drag doesn't restart the stream on every step. */}
         <div
           className="relative h-1.5 rounded-full bg-white/25 cursor-pointer group mb-2"
-          onClick={(e) => {
+          onPointerDown={(e) => {
-            const r = (e.currentTarget as HTMLElement).getBoundingClientRect();
+            const el = e.currentTarget as HTMLElement;
-            seekTo(((e.clientX - r.left) / r.width) * duration);
+            try {
+              el.setPointerCapture(e.pointerId);
+            } catch {
+              /* capture unavailable — dragging still works via buttons state */
+            }
+            const r = el.getBoundingClientRect();
+            const x = Math.max(0, Math.min(e.clientX - r.left, r.width));
+            setScrub((x / r.width) * duration);
           }}
-          onMouseMove={(e) => {
+          onPointerMove={(e) => {
             const r = (e.currentTarget as HTMLElement).getBoundingClientRect();
             const x = Math.max(0, Math.min(e.clientX - r.left, r.width));
-            setHover({ x, t: (x / r.width) * duration });
+            const tt = (x / r.width) * duration;
+            setHover({ x, t: tt });
+            if (e.buttons & 1) setScrub(tt); // dragging with the primary button held
+          }}
+          onPointerUp={() => {
+            if (scrub != null) {
+              seekTo(scrub);
+              setScrub(null);
+            }
           }}
           onMouseLeave={() => setHover(null)}
         >
@@ -1015,10 +1068,12 @@ export default function PlexPlayer({ itemId, onClose, queue }: Props) {
               style={{ left: `${(m.start_s / duration) * 100}%`, width: `${((m.end_s - m.start_s) / duration) * 100}%` }}
             />
           ))}
-          <div className="absolute inset-y-0 left-0 bg-accent rounded-full" style={{ width: `${pct}%` }} />
+          <div className="absolute inset-y-0 left-0 bg-accent rounded-full" style={{ width: `${headPct}%` }} />
           <div
-            className="absolute top-1/2 -translate-y-1/2 -translate-x-1/2 w-3 h-3 rounded-full bg-accent opacity-0 group-hover:opacity-100"
+            className={`absolute top-1/2 -translate-y-1/2 -translate-x-1/2 w-3 h-3 rounded-full bg-accent transition-opacity ${
-            style={{ left: `${pct}%` }}
+              scrub != null ? "opacity-100" : "opacity-0 group-hover:opacity-100"
+            }`}
+            style={{ left: `${headPct}%` }}
           />
         </div>
 
@@ -1047,15 +1102,17 @@ export default function PlexPlayer({ itemId, onClose, queue }: Props) {
             <Ctrl label={t("plex.player.mute")} onClick={toggleMute}>
               {muted || volume === 0 ? <VolumeX className="w-5 h-5" /> : <Volume2 className="w-5 h-5" />}
             </Ctrl>
-            {/* Custom volume bar: the track is a loudness gradient (blue = too quiet, green = normal,
+            {/* Volume bar: plain accent fill on a neutral track (as before); hover shows the 0–100
-                red = too loud); the reached level is bright, the rest dimmed; hover shows the 0–100
                 value under the cursor; click/drag sets it. */}
             <div
               ref={volBarRef}
-              className="relative h-1.5 w-24 cursor-pointer rounded-full"
+              className="relative h-1.5 w-24 cursor-pointer rounded-full bg-white/25"
-              style={{ background: "linear-gradient(to right,#3b82f6 0%,#22c55e 30%,#22c55e 68%,#ef4444 100%)" }}
               onPointerDown={(e) => {
+                try {
                   (e.currentTarget as HTMLElement).setPointerCapture(e.pointerId);
+                } catch {
+                  /* capture unavailable — dragging still works via buttons state */
+                }
                 const v = volAt(e.clientX);
                 setVol(v, v === 0);
               }}
@@ -1066,14 +1123,14 @@ export default function PlexPlayer({ itemId, onClose, queue }: Props) {
               }}
               onMouseLeave={() => setVolHover(null)}
             >
-              {/* dim the louder (unreached) part so the bright section reads as the current level */}
+              {/* filled level */}
               <div
-                className="absolute inset-y-0 right-0 rounded-full bg-black/55"
+                className="absolute inset-y-0 left-0 rounded-full bg-accent"
-                style={{ left: `${(muted ? 0 : volume) * 100}%` }}
+                style={{ width: `${(muted ? 0 : volume) * 100}%` }}
               />
               {/* thumb */}
               <div
-                className="absolute top-1/2 h-3 w-3 -translate-x-1/2 -translate-y-1/2 rounded-full bg-white shadow"
+                className="absolute top-1/2 h-3 w-3 -translate-x-1/2 -translate-y-1/2 rounded-full bg-accent shadow"
                 style={{ left: `${(muted ? 0 : volume) * 100}%` }}
               />
               {/* hover value tooltip (0–100), like the seek bar */}
@@ -1501,6 +1558,13 @@ export default function PlexPlayer({ itemId, onClose, queue }: Props) {
   );
 }
 
+// Renders nothing; while mounted it claims one history entry so the browser/mouse Back button runs
+// `onBack` (close the panel / cancel the skip) instead of navigating out of the player.
+function BackClose({ onBack }: { onBack: () => void }) {
+  useBackToClose(onBack);
+  return null;
+}
+
 // --- settings-panel building blocks ------------------------------------------------------------
 function PanelHead({ children }: { children: ReactNode }) {
   return <div className="px-1 pt-2 pb-1 text-[11px] uppercase tracking-wide text-white/50">{children}</div>;