domain: player/reporting ticks -> milliseconds (phase 4c)

Playback position now crosses the IPC boundary in milliseconds. Ticks
survive only inside Rust (DB storage, Jellyfin API) and at the genuine
remote-session boundary (session seek / transfer / RemoteControls).

Rust command signatures (ms in, converted to ticks internally):
- storage_update_playback_progress / _context: position_ms
- repository_report_playback_start / _progress / _stopped: position_ms
- PlaybackProgress.position_ticks -> position_ms (converted in the query)

Frontend:
- playbackReporting, playerEvents, VideoPlayer, Queue, player/[id] resume:
  seconds*1000 / durationMs/1000 instead of tick math.
- repository-client + syncService param names -> positionMs.
- Tests updated to ms fixtures/assertions.

Out of scope (legitimately ticks): NowPlayingItem, PlayState.positionTicks,
sessionSeek, playbackModeTransferToLocal, RemoteControls, SessionCard — the
remote Jellyfin session API.

Rust 456, frontend 644, check clean.

src/lib/components/player/VideoPlayer.svelte

@@ -165,9 +165,9 @@
   // Use known duration from media item (runTimeTicks is in 10M ticks/second)
   // Fallback to video element duration for direct streams
   const duration = $derived.by(() => {
-    // Explicitly check if runTimeTicks exists and is a valid number
-    if (media && media.runTimeTicks && media.runTimeTicks > 0) {
-      return media.runTimeTicks / 10_000_000;
+    // Explicitly check if durationMs exists and is a valid number
+    if (media && media.durationMs && media.durationMs > 0) {
+      return media.durationMs / 1000;
     }
     // Otherwise use the video element's duration
     return videoDuration;
@@ -386,7 +386,7 @@
             // Check if we're near the end of the video - if so, this is likely
             // end-of-stream rather than a real error. Jellyfin transcoded HLS
             // streams may not always terminate cleanly with #EXT-X-ENDLIST.
-            const knownDuration = media?.runTimeTicks ? media.runTimeTicks / 10_000_000 : videoDuration;
+            const knownDuration = media?.durationMs ? media.durationMs / 1000 : videoDuration;
             const effectiveTime = currentTime + seekOffset;
             const isNearEnd = knownDuration > 0 && effectiveTime > 0 && effectiveTime / knownDuration > 0.9;