feat(tksafety): 위험성평가 모듈 Phase 1 구현 — DB·API·Excel·프론트엔드

5개 테이블(risk_projects/processes/items/mitigations/templates) + 마스터 시딩,
프로젝트·항목·감소대책 CRUD API, ExcelJS 평가표 내보내기,
프로젝트 목록·평가 수행 페이지, 사진 업로드(multer), 네비게이션·CSS 추가.

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

tksafety/web/static/js/tksafety-core.js

@@ -111,6 +111,7 @@ function renderNavbar() {
         { href: '/entry-dashboard.html', icon: 'fa-id-card-alt', label: '출입 현황판', match: ['entry-dashboard.html'], admin: true },
         { href: '/education.html', icon: 'fa-graduation-cap', label: '안전교육', match: ['education.html'] },
         { href: '/training.html', icon: 'fa-chalkboard-teacher', label: '안전교육 실시', match: ['training.html'], admin: true },
+        { href: '/risk-projects.html', icon: 'fa-exclamation-triangle', label: '위험성평가', match: ['risk-projects.html', 'risk-assess.html'], admin: true },
         { href: '/checklist.html', icon: 'fa-tasks', label: '체크리스트 관리', match: ['checklist.html'], admin: true },
     ];
     const nav = document.getElementById('sideNav');