feat(music-render): providers/suno.py — 13 Suno API 함수 이식 (SP-5)

NAS music-lab/app/suno_provider.py를 Windows worker로 이식.
DB 호출(update_task, add_track 등)을 nas_client.webhook_*으로 변환.
결과 MP3는 MUSIC_MEDIA_ROOT(/mnt/nas/...)에 직접 저장.
13 함수: generation, extend, vocal_removal, cover_image, wav, stem_split,
upload_cover, upload_extend, add_vocals, add_instrumental, video_generate
+ _build_suno_payload + _poll_suno_record + _download_and_register
Plan-B-Music Phase 2.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

services/music-render/tests/test_suno_provider.py

@@ -0,0 +1,32 @@
+"""providers/suno.py — _build_suno_payload 단위 테스트 + 1개 함수 mock 검증."""
+import pytest
+from providers.suno import _build_suno_payload
+
+
+def test_payload_custom_mode_with_lyrics():
+    params = {"lyrics": "[Verse]\nhello", "genre": "lofi", "moods": ["chill"], "model": "V4"}
+    p = _build_suno_payload(params)
+    assert p["customMode"] is True
+    assert p["prompt"] == "[Verse]\nhello"
+    assert "lofi" in p["style"]
+    assert "chill" in p["style"]
+
+
+def test_payload_simple_mode_no_lyrics_no_genre():
+    params = {"prompt": "happy summer", "model": "V4"}
+    p = _build_suno_payload(params)
+    assert p["customMode"] is False
+    assert "happy summer" in p["prompt"]
+
+
+def test_payload_instrumental_clears_prompt():
+    params = {"genre": "ambient", "instrumental": True, "model": "V5"}
+    p = _build_suno_payload(params)
+    assert p["instrumental"] is True
+    assert p["prompt"] == ""
+
+
+def test_payload_includes_optional_vocal_gender():
+    params = {"genre": "pop", "vocal_gender": "f", "model": "V4"}
+    p = _build_suno_payload(params)
+    assert p["vocalGender"] == "f"