시리즈 네비게이션과 댓글 시스템

CREATE TABLE series (
  id UUID DEFAULT gen_random_uuid() PRIMARY KEY,
  title TEXT NOT NULL,
  slug TEXT NOT NULL UNIQUE,
  description TEXT DEFAULT '',
  published BOOLEAN DEFAULT false,
  title_en TEXT DEFAULT '',
  description_en TEXT DEFAULT ''
);

-- posts에 시리즈 연결
ALTER TABLE posts ADD COLUMN series_id UUID REFERENCES series(id) ON DELETE SET NULL;
ALTER TABLE posts ADD COLUMN series_order INTEGER DEFAULT 0;

// 시리즈 데이터 fetch
useEffect(() => {
  if (!post.series_id) return;
  fetch(`/api/series/${post.series_id}`)
    .then(res => res.json())
    .then(data => setSeriesData(data));
}, [post.series_id]);

const currentOrder = seriesPosts.findIndex(p => p.slug === post.slug);
const prevPost = currentOrder > 0 ? seriesPosts[currentOrder - 1] : null;
const nextPost = currentOrder < seriesPosts.length - 1
  ? seriesPosts[currentOrder + 1] : null;

CREATE TABLE comments (
  id UUID DEFAULT gen_random_uuid() PRIMARY KEY,
  post_id UUID NOT NULL REFERENCES posts(id) ON DELETE CASCADE,
  parent_id UUID REFERENCES comments(id) ON DELETE CASCADE,
  nickname TEXT NOT NULL,
  password_hash TEXT NOT NULL,
  content TEXT NOT NULL,
  is_admin BOOLEAN DEFAULT false,
  created_at TIMESTAMPTZ DEFAULT now()
);

const grouped = comments.reduce((acc, comment) => {
  if (!comment.parent_id) {
    // 최상위 댓글
    acc.push({ ...comment, replies: [] });
  } else {
    // 대댓글 → 부모 찾아서 replies에 추가
    const parent = acc.find(c => c.id === comment.parent_id);
    if (parent) parent.replies.push(comment);
  }
  return acc;
}, []);

CREATE TABLE likes (
  id UUID DEFAULT gen_random_uuid() PRIMARY KEY,
  target_type TEXT NOT NULL,  -- 'post' | 'work'
  target_id TEXT NOT NULL,
  ip TEXT NOT NULL,
  UNIQUE (target_type, target_id, ip)
);