feat(logs): date filter + clear log endpoints

- API GET /api/logs now accepts from_ts / to_ts (unix epoch, half-open
  [from, to)) so callers can scope by arbitrary time range.
- API DELETE /api/logs added. Same from_ts / to_ts semantics. No params
  = wipe everything and reset the AUTOINCREMENT counter.
- Dashboard Logs page: date picker that scopes both the view and the
  delete button to the selected day in the user's local timezone. The
  clear button is red and confirms before deleting; label switches
  between "전체 로그 초기화" and "<날짜> 하루치 삭제".

README.md

@@ -88,7 +88,8 @@ mc-filter-proxy 컨테이너 (25565)
 | POST   | `/api/domains`                  | 도메인 추가                             |
 | PATCH  | `/api/domains/{domain}`         | 활성/메모 변경                          |
 | DELETE | `/api/domains/{domain}`         | 도메인 삭제                             |
-| GET    | `/api/logs?limit&offset&action` | 접속 로그 (페이지네이션)                |
+| GET    | `/api/logs?limit&offset&action&from_ts&to_ts` | 접속 로그 (페이지네이션, 날짜 필터) |
+| DELETE | `/api/logs?from_ts&to_ts`       | 접속 로그 삭제 (범위 미지정 시 전체)      |
 | GET    | `/api/status`                   | 프록시 상태 + 통계                      |
 | POST   | `/api/proxy/restart`            | config 파일 touch (프록시 재로드 트리거) |