- Speed is no longer part of Kokoro generation, in-memory cache keys, or
MinIO object keys — audio is always generated at 1.0 and playback speed
is applied client-side via audioEl.playbackRate
- presignAudio() now calls rewriteHost() so chapter audio URLs use the
public MinIO endpoint (same as presignVoiceSample already did)
- docker-compose.yml: rename MINIO_PUBLIC_ENDPOINT → PUBLIC_MINIO_PUBLIC_URL
for the ui service so SvelteKit's $env/dynamic/public picks it up