feat(node-player): use Service Worker for auth, enable streaming playback

Add a Service Worker that intercepts /api/* requests and injects the
Bearer token. This allows <audio> and <img> elements to use direct
URLs instead of downloading entire files as blobs first.

- Audio now streams progressively (no full download before playback)
- Cover art loads via regular <img src> (SW adds auth header)
- Remove blob-based preloadStream, fetchCoverBlob, useCoverUrl hook
- Register SW in main.tsx, token synced via postMessage

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

furumi-node-player/client/src/components/QueueList.tsx

@@ -1,5 +1,5 @@
 import { useEffect, useRef, useState } from 'react'
-import { useCoverUrl } from '../hooks/useCoverUrl'
+import { API_ROOT } from '../furumiApi'
 
 export type QueueItem = {
   slug: string
@@ -32,11 +32,10 @@ function fmt(secs: number) {
   return `${m}:${pad(s % 60)}`
 }
 
-function Cover({ slug }: { slug: string }) {
+function Cover({ src }: { src: string }) {
   const [errored, setErrored] = useState(false)
-  const src = useCoverUrl(slug)
-
-  if (!src || errored) return <>&#127925;</>
+  useEffect(() => { setErrored(false) }, [src])
+  if (errored) return <>&#127925;</>
   return <img src={src} alt="" onError={() => setErrored(true)} />
 }
 
@@ -75,7 +74,7 @@ export function QueueList({
         if (!t) return null
 
         const isPlaying = origIdx === playingOrigIdx
-        const hasAlbum = !!t.album_slug
+        const coverSrc = t.album_slug ? `${API_ROOT}/tracks/${t.slug}/cover` : ''
         const dur = t.duration ? fmt(t.duration) : ''
         const isDragging = draggingPos === pos
         const isDragOver = dragOverPos === pos
@@ -116,7 +115,7 @@ export function QueueList({
           >
             <span className="qi-index">{isPlaying ? '' : pos + 1}</span>
             <div className="qi-cover">
-              {hasAlbum ? <Cover slug={t.slug} /> : <>&#127925;</>}
+              {coverSrc ? <Cover src={coverSrc} /> : <>&#127925;</>}
             </div>
             <div className="qi-info">
               <div className="qi-title">{t.title}</div>