feat(phase3b): music_video 제품 시드 + music_tracks video 컬럼 마이그레이션

Phase 3b Task 1: DB 마이그레이션
- products에 'music_video' 제품 생성 (30000원)
- music_tracks에 video_status/video_url/video_order_id 컬럼 추가

의존성: 2026-07-03-phase3a-music.sql 적용 후 실행

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01AAtcmKKtqDUe4NyVgy1aLQ

supabase/migrations/2026-07-09-phase3b-music-video.sql

@@ -0,0 +1,13 @@
+-- Phase 3b (2026-07-09): 음악 영상화 발주
+-- 의존성: 2026-07-03-phase3a-music.sql(music_tracks) 적용 후
+-- 적용: 클라우드 Supabase + NAS self-host 양쪽
+
+INSERT INTO products (id, name, price, category, is_active)
+VALUES ('music_video', '음악 영상화', 30000, 'software', true)
+ON CONFLICT (id) DO NOTHING;
+
+ALTER TABLE music_tracks
+  ADD COLUMN IF NOT EXISTS video_status text NOT NULL DEFAULT 'none'
+    CHECK (video_status IN ('none','requested','in_progress','delivered')),
+  ADD COLUMN IF NOT EXISTS video_url text,
+  ADD COLUMN IF NOT EXISTS video_order_id uuid;