Fix Nuggets workflow audio: serve with audio content type (nosniff blocked octet-stream), show playback errors; v2.17.1

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

src/AdminPage.tsx

@@ -1751,7 +1751,19 @@ function NuggetsWorkflowAdmin() {
 
                         {s.key === 'listen' && (
                           <div style={{ marginTop: 8 }}>
-                            <audio controls preload="none" style={{ width: '100%' }} src={`/api/admin/nuggets-workflow/${selected.id}/audio`} />
+                            <audio
+                              key={selected.id}
+                              controls
+                              preload="none"
+                              style={{ width: '100%' }}
+                              src={`/api/admin/nuggets-workflow/${selected.id}/audio`}
+                              onError={async () => {
+                                const r = await fetch(`/api/admin/nuggets-workflow/${selected.id}/audio`, { headers: { Range: 'bytes=0-0' } }).catch(() => null)
+                                if (!r) setError('Audio request failed (network).')
+                                else if (r.ok) setError('The server sent the audio but the browser could not play it. The file may be in an unsupported format.')
+                                else setError(`Audio unavailable (${r.status}): ${(await r.json().catch(() => ({}))).message ?? 'unknown error'}`)
+                              }}
+                            />
                           </div>
                         )}
                         {s.key === 'coldOpen' && (