fix(update.sh): remove stale downloader-fast call

That service was merged into llama-server a while back (see the
comment on llama-server-fast's old alias), but update.sh's set -euo
pipefail meant every run since has hard-exited there — silently
skipping downloader-comfyui and the final `docker compose up -d`
recreate step on every invocation.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

scripts/update.sh

@@ -226,7 +226,6 @@ docker compose build --pull
 
 echo "==> ensuring models are downloaded (skips already-present files)"
 docker compose --profile tools run --rm downloader
-docker compose --profile tools run --rm downloader-fast
 docker compose --profile tools run --rm downloader-classifier
 docker compose --profile tools run --rm downloader-comfyui