fix: stop hardcoding MELO_SPEED so the .env override reaches the worker

supervisord.conf passed MELO_DEVICE through as %(ENV_MELO_DEVICE)s but pinned
MELO_SPEED="1.5", so lowering MELO_SPEED in .env had no effect — the worker
always got 1.5. Pass MELO_SPEED through with %(ENV_MELO_SPEED)s and set a
compose default (MELO_SPEED=${MELO_SPEED:-1.5}, same pattern as MELO_DEVICE) so
the supervisord expansion always resolves and an .env value actually changes
the speaking rate. Default rate is unchanged (1.5). melo_worker logs the
resolved speed at startup, so the env->worker path is verifiable.

Verified: _resolve_speed() returns 1.1 for MELO_SPEED=1.1 (1.5 otherwise), and
`MELO_SPEED=1.1 docker compose config` renders MELO_SPEED: "1.1" into the env.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

docker-compose.yml

@@ -69,6 +69,10 @@ services:
       # MeloTTS on the GPU (cu128 torch baked by docker/setup-melo.sh). CPU synth
       # serialised under load and pushed TTS to 7-8s; GPU does ~0.3s/sentence.
       MELO_DEVICE: ${MELO_DEVICE:-cuda}
+      # Speaking rate for MeloTTS. Set here (with a default) so supervisord's
+      # %(ENV_MELO_SPEED)s passthrough always resolves and an .env override
+      # actually reaches the melo-worker. Lower it (e.g. 1.1) for a calmer pace.
+      MELO_SPEED: ${MELO_SPEED:-1.5}
       # Optional single-language lock for replies (empty = user's own language).
       OUTPUT_LANGUAGE: ${OUTPUT_LANGUAGE:-ko}
       # Drop the pre-loop planner LLM call to cut voice-reply latency on small

docker/supervisord.conf

@@ -61,10 +61,13 @@ directory=/app
 ; HF_HUB_OFFLINE/TRANSFORMERS_OFFLINE force pure-cache reads: the pinned old
 ; transformers/huggingface_hub otherwise retry the network on every load and
 ; error out instead of falling back to the (complete) baked cache.
-; MELO_DEVICE inherits from the container env (compose sets it; default cuda)
-; so the worker runs MeloTTS on the GPU. supervisord interpolates %(ENV_x)s
-; from its own environment, which is the container's.
-environment=MELO_LANGUAGE="KR",MELO_SPEED="1.5",MELO_DEVICE="%(ENV_MELO_DEVICE)s",MELO_WORKER_HOST="127.0.0.1",MELO_WORKER_PORT="8770",HF_HOME="/opt/melo-cache",HF_HUB_OFFLINE="1",TRANSFORMERS_OFFLINE="1"
+; MELO_DEVICE and MELO_SPEED inherit from the container env (compose sets both
+; with defaults: cuda / 1.5) so the worker runs MeloTTS on the GPU at the
+; configured rate. supervisord interpolates %(ENV_x)s from its own environment,
+; which is the container's — so MELO_SPEED must always be set in the env
+; (compose guarantees it) or this expansion fails at startup. Hardcoding 1.5
+; here previously shadowed the .env value, so lowering MELO_SPEED had no effect.
+environment=MELO_LANGUAGE="KR",MELO_SPEED="%(ENV_MELO_SPEED)s",MELO_DEVICE="%(ENV_MELO_DEVICE)s",MELO_WORKER_HOST="127.0.0.1",MELO_WORKER_PORT="8770",HF_HOME="/opt/melo-cache",HF_HUB_OFFLINE="1",TRANSFORMERS_OFFLINE="1"
 priority=280
 autorestart=true
 stdout_logfile=/dev/stdout