feat(server): 라우트 전면 개편 — 반응·가시성·댓글/대댓글·삭제

- GET / : 내 프로젝트/피드 분리, role 도구 필터, 댓글 일괄 조회(commentsByProject)
- 반응(heart/star) AJAX JSON, visibility/delete(본인), 댓글/대댓글(parent_id)
- 댓글 LGTM/🚀 egg 신호 + return_to 복귀, isAjax/safeBack 헬퍼
- res.locals 로 icon/identicon/langColor 노출
- db: listCommentsByProjects 추가, _header: body 시작 신호(toast/egg/open)

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/db.js

@@ -57,6 +57,18 @@ export async function listComments(projectId) {
   return rows;
 }
 
+// 여러 프로젝트의 댓글을 한 번에 (대시보드 모달 저장소용). parent_id 포함.
+export async function listCommentsByProjects(ids) {
+  if (!ids || !ids.length) return [];
+  const { rows } = await q(
+    `SELECT c.*, u.name AS author_name
+       FROM comments c JOIN users u ON u.sabun=c.author_sabun
+      WHERE c.project_id = ANY($1::bigint[]) ORDER BY c.created_at ASC`,
+    [ids]
+  );
+  return rows;
+}
+
 export async function addProject({ owner, title, description, repoUrl, appUrl, tags, isPublic, lang }) {
   const { rows } = await q(
     `INSERT INTO projects (owner_sabun, title, description, repo_url, app_url, tags, is_public, lang)