test: add MeloTTS-Korean browser test harness

melo-test/ contains a minimal FastAPI server + static HTML UI for
auditioning MeloTTS-Korean before wiring it into the bot:

- server.py: POST /tts -> wav, model loaded once at startup
- index.html: textarea + presets + audio player, shows synth latency
- requirements.txt / README.md: setup steps

Directory is melo-test/ because the repo .gitignore already excludes
test/. Discord-bot integration is unchanged in this branch; this is a
local audition harness only.

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

melo-test/.gitignore

@@ -0,0 +1,5 @@
+.venv/
+__pycache__/
+*.pyc
+*.wav
+*.mp3