fix: 배포 후 버그 수정 — 테이블명/컬럼명 불일치, navbar active, API 검증 강화, 대시보드 통계 라우트 추가

- checkinModel: partner_checkins → partner_work_checkins, countActive() 추가
- workReportModel: partner_work_reports → daily_work_reports
- partner-portal: check_out_at/check_in_at → check_out_time/check_in_time
- checkinModel findTodayByCompany: LEFT JOIN has_work_report
- tkpurchase-core/tksafety-core: navbar match '' 제거
- checkinController: checkOut에 업무현황 검증, stats() 추가
- workReportController: checkin_id 필수 + schedule 일치 검증
- checkinRoutes: GET / 대시보드 통계 라우트 추가
- nginx.conf: visit.html → tksafety 리다이렉트
- migration-purchase-safety.sql: DDL 동기화
- migration-purchase-safety-patch.sql: 신규 패치

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

scripts/migration-purchase-safety-patch.sql

@@ -0,0 +1,11 @@
+-- migration-purchase-safety-patch.sql
+-- 배포 후 스키마 보완 패치
+-- 생성일: 2026-03-13
+
+-- 4-a. check_in_time NOT NULL (체크인 시 시간은 항상 존재)
+ALTER TABLE partner_work_checkins
+  MODIFY check_in_time DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP;
+
+-- 4-b. 일정당 하루 1건 업무보고 보장
+ALTER TABLE daily_work_reports
+  ADD UNIQUE INDEX uq_schedule_report_date (schedule_id, report_date);

scripts/migration-purchase-safety.sql

@@ -86,7 +86,7 @@ CREATE TABLE IF NOT EXISTS partner_work_checkins (
   schedule_id         INT NOT NULL,
   company_id          INT NOT NULL,
   checked_by          INT NOT NULL,
-  check_in_time       DATETIME,
+  check_in_time       DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
   check_out_time      DATETIME,
   worker_names        TEXT,
   actual_worker_count INT,
@@ -118,6 +118,7 @@ CREATE TABLE IF NOT EXISTS daily_work_reports (
   updated_at      TIMESTAMP DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
   INDEX idx_daily_report_date (report_date),
   INDEX idx_daily_report_schedule (schedule_id),
+  UNIQUE INDEX uq_schedule_report_date (schedule_id, report_date),
   CONSTRAINT fk_daily_reports_schedule
     FOREIGN KEY (schedule_id) REFERENCES partner_schedules(id),
   CONSTRAINT fk_daily_reports_checkin