domain: catalog frontend off Jellyfin ticks -> milliseconds (phase 3a)

The catalog surface now speaks milliseconds, the app's neutral time unit.
Ticks no longer reach library/home components.

Rust:
- UserData gains playback_position_ms (dual-carry), populated from ticks
  at the offline mapping seam via domain::ticks_to_ms.

Frontend:
- formatDuration(duration.ts) and the two local copies now take ms, not
  ticks; all callers pass item.durationMs.
- Progress bars (EpisodeRow, EpisodeFocusView, MediaCard, LibraryListView)
  compute playbackPositionMs / durationMs — unit-consistent, no tick math.
- PlaylistDetailView totalDuration sums durationMs.
- duration.test.ts + TrackList.test.ts fixtures updated to ms.

Deferred: player/session/reporting tick math (Queue, SessionCard,
RemoteControls, playbackReporting, playerEvents) — those cross the
storage/Jellyfin command boundary in ticks and need command-signature
changes (phase 3b). Display {item.type} badge -> kind label (phase 4).

Rust 456, frontend 644, check + check:boundary clean.

src/lib/components/library/EpisodeFocusView.svelte

@@ -86,9 +86,9 @@
     return null;
   });
 
-  function formatDuration(ticks?: number | null): string {
-    if (!ticks) return "";
-    const seconds = Math.floor(ticks / 10000000);
+  function formatDuration(ms?: number | null): string {
+    if (!ms) return "";
+    const seconds = Math.floor(ms / 1000);
     const hours = Math.floor(seconds / 3600);
     const minutes = Math.floor((seconds % 3600) / 60);
 
@@ -99,10 +99,10 @@
   }
 
   function getProgress(ep: MediaItem): number {
-    if (!ep.userData || !ep.runTimeTicks) {
+    if (!ep.userData || !ep.durationMs) {
       return 0;
     }
-    return ((ep.userData.playbackPositionTicks ?? 0) / ep.runTimeTicks) * 100;
+    return ((ep.userData.playbackPositionMs ?? 0) / ep.durationMs) * 100;
   }
 
   function handlePlay() {
@@ -116,7 +116,7 @@
   const episodeLabel = $derived(
     `S${episode.parentIndexNumber || 1}E${episode.indexNumber || 1}`
   );
-  const duration = $derived(formatDuration(episode.runTimeTicks));
+  const duration = $derived(formatDuration(episode.durationMs));
   const progress = $derived(getProgress(episode));
 </script>
 

src/lib/components/library/EpisodeRow.svelte

@@ -38,13 +38,13 @@
   const downloadProgress = $derived(downloadInfo?.progress || 0);
 
   const progress = $derived(() => {
-    if (!episode.userData || !episode.runTimeTicks) {
+    if (!episode.userData || !episode.durationMs) {
       return 0;
     }
-    return ((episode.userData.playbackPositionTicks ?? 0) / episode.runTimeTicks) * 100;
+    return ((episode.userData.playbackPositionMs ?? 0) / episode.durationMs) * 100;
   });
 
-  const duration = $derived(formatDuration(episode.runTimeTicks));
+  const duration = $derived(formatDuration(episode.durationMs));
   const episodeNumber = $derived(episode.indexNumber || 0);
 </script>
 

src/lib/components/library/LibraryListView.svelte

@@ -42,10 +42,10 @@
 
 
   function getProgress(item: MediaItem | Library): number {
-    if (!showProgress || !("userData" in item) || !item.userData || !("runTimeTicks" in item) || !item.runTimeTicks) {
+    if (!showProgress || !("userData" in item) || !item.userData || !("durationMs" in item) || !item.durationMs) {
       return 0;
     }
-    return ((item.userData.playbackPositionTicks ?? 0) / item.runTimeTicks) * 100;
+    return ((item.userData.playbackPositionMs ?? 0) / item.durationMs) * 100;
   }
 
   function getTrackNumber(item: MediaItem | Library): string {
@@ -59,7 +59,7 @@
 <div class="space-y-1">
   {#each items as item, index (item.id)}
     {@const subtitle = getSubtitle(item)}
-    {@const duration = "runTimeTicks" in item ? formatDuration(item.runTimeTicks) : ""}
+    {@const duration = "durationMs" in item ? formatDuration(item.durationMs) : ""}
     {@const progress = getProgress(item)}
     {@const trackNum = getTrackNumber(item)}
     {@const isPlayed = "userData" in item && item.userData?.isPlayed}

src/lib/components/library/MediaCard.svelte

@@ -119,10 +119,10 @@
   const maxWidth = $derived(size === "large" ? 400 : size === "medium" ? 300 : 200);
 
   const progress = $derived(() => {
-    if (!showProgress || !("userData" in item) || !item.userData || !item.runTimeTicks) {
+    if (!showProgress || !("userData" in item) || !item.userData || !item.durationMs) {
       return 0;
     }
-    return ((item.userData.playbackPositionTicks ?? 0) / item.runTimeTicks) * 100;
+    return ((item.userData.playbackPositionMs ?? 0) / item.durationMs) * 100;
   });
 
   const subtitle = $derived(() => {

src/lib/components/library/PlaylistDetailView.svelte

@@ -25,7 +25,7 @@
   const tracks = $derived(entries.map(e => ({ ...e } as MediaItem)));
 
   const totalDuration = $derived(
-    entries.reduce((sum, e) => sum + (e.runTimeTicks ?? 0), 0)
+    entries.reduce((sum, e) => sum + (e.durationMs ?? 0), 0)
   );
 
   onMount(() => {

src/lib/components/library/TrackList.svelte

@@ -283,7 +283,7 @@
 
           <!-- Duration -->
           <div class="text-gray-400 text-right">
-            {formatDuration(track.runTimeTicks)}
+            {formatDuration(track.durationMs)}
           </div>
 
           <!-- Download Button Placeholder -->
@@ -421,7 +421,7 @@
             </p>
           </div>
           <div class="text-gray-400 text-sm {showDownload ? 'mr-20' : 'mr-12'}">
-            {formatDuration(track.runTimeTicks)}
+            {formatDuration(track.durationMs)}
           </div>
         </button>
 

src/lib/components/library/TrackList.test.ts

@@ -72,7 +72,7 @@ describe("TrackList", () => {
       artists: ["Artist 1"],
       albumName: "Album 1",
       albumId: "album-1",
-      runTimeTicks: 1800000000, // 3 minutes
+      durationMs: 180000, // 3 minutes
       primaryImageTag: "tag1",
       indexNumber: 1,
     },
@@ -84,7 +84,7 @@ describe("TrackList", () => {
       artists: ["Artist 2"],
       albumName: "Album 2",
       albumId: "album-2",
-      runTimeTicks: 2400000000, // 4 minutes
+      durationMs: 240000, // 4 minutes
       primaryImageTag: "tag2",
       indexNumber: 2,
     },
@@ -96,7 +96,7 @@ describe("TrackList", () => {
       artists: ["Artist 3", "Artist 4"],
       albumName: "Album 3",
       albumId: "album-3",
-      runTimeTicks: 3000000000, // 5 minutes
+      durationMs: 300000, // 5 minutes
       indexNumber: 3,
     },
   ];
@@ -187,7 +187,7 @@ describe("TrackList", () => {
       const tracksWithoutDuration: MediaItem[] = [
         {
           ...mockTracks[0],
-          runTimeTicks: undefined,
+          durationMs: undefined,
         },
       ];