feat: TKB shift scheduler — personnel shift planning web app

Full rewrite of METRO HMG for TKB tunnel department:
- People-based grid (18 TKB + 5 IT), year-long calendar
- Color-coded shift values (4/6/8/12/A/B/D/N/U/O)
- Drag-and-drop cells, multi-cell selection (click/ctrl/shift/drag)
- Right-click context menu with color palette
- Tunnel closure + Metro + D8 info rows (toggleable)
- Czech holidays highlighted with names
- PDF export (2-page A4 landscape, DejaVu font for Czech chars)
- Improvement proposals system
- Sticky headers (vertical + horizontal scroll)
- Cell value filter toggles in legend

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

web/package.json

@@ -0,0 +1,38 @@
+{
+  "name": "web",
+  "private": true,
+  "version": "0.0.0",
+  "type": "module",
+  "scripts": {
+    "dev": "vite",
+    "build": "tsc -b && vite build",
+    "start": "npm run build && node server.js",
+    "serve": "node server.js",
+    "lint": "eslint .",
+    "preview": "vite preview"
+  },
+  "dependencies": {
+    "exceljs": "^4.4.0",
+    "express": "^5.2.1",
+    "jspdf": "^4.2.1",
+    "multer": "^2.1.1",
+    "react": "^19.2.4",
+    "react-dom": "^19.2.4"
+  },
+  "devDependencies": {
+    "@eslint/js": "^9.39.4",
+    "@tailwindcss/vite": "^4.2.2",
+    "@types/node": "^24.12.0",
+    "@types/react": "^19.2.14",
+    "@types/react-dom": "^19.2.3",
+    "@vitejs/plugin-react": "^6.0.1",
+    "eslint": "^9.39.4",
+    "eslint-plugin-react-hooks": "^7.0.1",
+    "eslint-plugin-react-refresh": "^0.5.2",
+    "globals": "^17.4.0",
+    "tailwindcss": "^4.2.2",
+    "typescript": "~5.9.3",
+    "typescript-eslint": "^8.57.0",
+    "vite": "^8.0.1"
+  }
+}