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/requirements.txt

@@ -0,0 +1,7 @@
+# MeloTTS 본체는 PyPI 패키지 이름이 바뀌어 git 직접 설치가 가장 안전.
+# (https://github.com/myshell-ai/MeloTTS)
+git+https://github.com/myshell-ai/MeloTTS.git@main
+
+fastapi>=0.110
+uvicorn[standard]>=0.27
+pydantic>=2.0