fix: review round 1 — row press after a rename, related reset, dead items on removal, honest Prev/Next

- A press that begins while a field in the row is edited only ends the editing (rowOpen latches it
  at pointerdown); the card layout's row press is now tested.
- A related video reset in the player forgets the session's stored position.
- Removing the playing video passes over known-dead items and steps the way it went.
- Prev/Next off only because of dead items stay focusable and say why (HU/EN).
- The docked bar's scroller leaves room for focus rings.
- A focus-opened About card is not closed by its own scroll into view.
- EN "Clear watch progress" for the video reset, distinct from a page's "Reset view".
- The signed-out title read goes to the page yt-dlp read; the retitle writes are conditional.
- Tests: the cap of three errors, the bar's own Fullscreen, the group glyph, the backfill's reads.

frontend/src/features/player/playerModalControls.tsx

@@ -5,6 +5,7 @@ import type { VideoDetail } from "../../lib/api";
 import type { AutoMode, LoopMode } from "../../lib/playerModes";
 import { IconButton } from "../../components/ui/IconButton";
 import { StateMessage } from "../../components/ui/QueryState";
+import { unavailable } from "../../components/ui/unavailable";
 import { ClampedText } from "../../components/ui/ClampedText";
 import { renderDescription } from "./descriptionLinks";
 
@@ -28,6 +29,8 @@ export function PlayerTransportControls({
   queueLength,
   canPrev,
   canNext,
+  prevReason,
+  nextReason,
   autoMode,
   loopMode,
   onPrev,
@@ -41,6 +44,11 @@ export function PlayerTransportControls({
   /** Whether there is a playable item that way (one YouTube refused is passed over). */
   canPrev: boolean;
   canNext: boolean;
+  /** Why Previous / Next are off when items are left that way (only ones YouTube refused): the
+   *  button stays focusable and its tooltip says so. Unset at the queue's ends, which explain
+   *  themselves. */
+  prevReason?: string;
+  nextReason?: string;
   autoMode: AutoMode;
   loopMode: LoopMode;
   onPrev: () => void;
@@ -62,6 +70,7 @@ export function PlayerTransportControls({
     title: string;
     onClick: () => void;
     disabled?: boolean;
+    reason?: string;
     lit?: boolean;
   };
   const step: Control[] = [
@@ -72,6 +81,7 @@ export function PlayerTransportControls({
       title: `${t("player.previous")} · Shift+←`,
       onClick: onPrev,
       disabled: !canPrev,
+      reason: canPrev ? undefined : prevReason,
     },
     {
       key: "next",
@@ -80,6 +90,7 @@ export function PlayerTransportControls({
       title: `${t("player.next")} · Shift+→`,
       onClick: onNext,
       disabled: !canNext,
+      reason: canNext ? undefined : nextReason,
     },
   ];
   // Persistent playback settings — cycle on click, saved to your account.
@@ -107,10 +118,10 @@ export function PlayerTransportControls({
       key={c.key}
       variant={docked ? "overlay" : undefined}
       onClick={c.onClick}
-      disabled={c.disabled}
+      {...unavailable(c.disabled, c.reason)}
       lit={c.lit}
       label={c.name}
-      title={c.title}
+      title={c.reason ? `${c.title} · ${c.reason}` : c.title}
     >
       {c.glyph}
     </IconButton>