fix(plex): a card offers Restart by the menu's own "started" rule

The picture read "started" off the rounded progress %, so a resume point under 1 % showed Play
while the card's menu offered "from the start". Both use `plexStarted` now.

frontend/src/components/plexCards.dom.test.tsx

@@ -208,6 +208,19 @@ describe("a started Plex card", () => {
     expect(container.querySelector(".flex-col.reveal-hover")).toBeNull();
   });
 
+  // E28 review D4: the card read "started" off the rounded progress %, the menu off the position —
+  // 20 s into a 3 h film is 0 % here and started there, so the card offered no Restart the menu had.
+  it("a resume point under 1 % still offers the Restart, as the card's menu does", () => {
+    render(
+      <PlexPosterCard
+        card={{ ...movie("in_progress"), position_seconds: 20, duration_seconds: 10800 }}
+        onOpen={vi.fn()}
+        onRestart={vi.fn()}
+      />,
+    );
+    expect(screen.getByRole("button", { name: "card.restart" })).toBeTruthy();
+  });
+
   it("a not-started or watched card keeps the one Play", () => {
     render(<PlexPosterCard card={movie("watched")} onOpen={vi.fn()} onRestart={vi.fn()} />);
     expect(screen.queryByRole("button", { name: "card.restart" })).toBeNull();

frontend/src/components/plexCards.tsx

@@ -7,7 +7,7 @@ import { Carousel } from "./ui/Carousel";
 import type { PlexCard, PlexCastMember, PlexFilters, PlexSeasonDetail } from "../lib/api";
 import { navItemAttrs } from "../lib/listNav";
 import { endsTextSelection, movedPastSlop } from "../lib/textSelection";
-import { plexAddLabelKey } from "./usePlexCardActions";
+import { plexAddLabelKey, plexStarted } from "./usePlexCardActions";
 import { IconButton } from "./ui/IconButton";
 import { MoreButton } from "./ui/MoreButton";
 import { Pressable } from "./ui/Pressable";
@@ -186,6 +186,7 @@ function PlexPicture({
   plays,
   small = false,
   pct = 0,
+  started = false,
   bar,
   children,
 }: {
@@ -201,23 +202,26 @@ function PlexPicture({
   /** A shelf's short landscape picture: the smaller Play, clear of the hover row under it. */
   small?: boolean;
   pct?: number;
+  /** Has a resume point (`plexStarted`, the card menu's own rule): Continue + Restart, not Play. */
+  started?: boolean;
   bar: ReactNode;
   /** The badges printed on the picture. */
   children?: ReactNode;
 }) {
-  // The pct is the resume point's: a watched or untouched item has none, and plays from its start.
-  const started = plays && pct > 0 && !!onRestart;
+  // Not read off `pct`: that is rounded, so 20 s into a 3 h film was 0 % and "not started" here while
+  // the menu offered "from the start" (E28 review D4). One rule, `plexStarted`, for both.
+  const resumable = plays && started && !!onRestart;
   return (
     <div className={mediaPictureBox(aspect)}>
       <Pressable onClick={onOpen} aria-label={label} data-nav-open="" className={MEDIA_PICTURE}>
         <img src={thumb} alt="" loading="lazy" decoding="async" className={MEDIA_IMG} />
         {children}
         <div className={MEDIA_HOVER_LAYER}>
-          {plays && !started && <MediaPlayGlyph small={small} />}
+          {plays && !resumable && <MediaPlayGlyph small={small} />}
         </div>
         <MediaProgress pct={pct} />
       </Pressable>
-      {started && (
+      {resumable && (
         <div
           className={clsx(
             HOVER_REVEAL,
@@ -332,6 +336,7 @@ export function PlexPosterCard({
             plays={isPlayable}
             small={shelf && landscape}
             pct={pct}
+            started={plexStarted(acted)}
             bar={
               <HoverBar
                 watched={actedWatched}
@@ -647,6 +652,7 @@ export function EpisodeCard({
           onRestart={onRestart}
           plays
           pct={pct}
+          started={plexStarted(ep)}
           bar={
             <HoverBar
               watched={watched}