Security+UX: Add DOMPurify XSS protection, security headers, admin auth gate, import file size limit, due date color coding, swipe/scroll conflict prevention

package-lock.json

@@ -12,8 +12,10 @@
         "@dnd-kit/sortable": "^10.0.0",
         "@dnd-kit/utilities": "^3.2.2",
         "@prisma/client": "^6.19.3",
+        "@types/dompurify": "^3.2.0",
         "bcryptjs": "^3.0.3",
         "csv-parse": "^7.0.2",
+        "dompurify": "^3.4.14",
         "marked": "^18.0.10",
         "next": "16.3.1",
         "next-auth": "^4.24.15",
@@ -1686,6 +1688,15 @@
         "@types/ms": "*"
       }
     },
+    "node_modules/@types/dompurify": {
+      "version": "3.2.0",
+      "resolved": "https://registry.npmjs.org/@types/dompurify/-/dompurify-3.2.0.tgz",
+      "integrity": "sha512-Fgg31wv9QbLDA0SpTOXO3MaxySc4DKGLi8sna4/Utjo4r3ZRPdCt4UQee8BWr+Q5z21yifghREPJGYaEOEIACg==",
+      "deprecated": "This is a stub types definition. dompurify provides its own type definitions, so you do not need this installed.",
+      "dependencies": {
+        "dompurify": "*"
+      }
+    },
     "node_modules/@types/estree": {
       "version": "1.0.9",
       "resolved": "https://registry.npmjs.org/@types/estree/-/estree-1.0.9.tgz",
@@ -1758,6 +1769,12 @@
         "@types/react": "^19.2.0"
       }
     },
+    "node_modules/@types/trusted-types": {
+      "version": "2.0.7",
+      "resolved": "https://registry.npmjs.org/@types/trusted-types/-/trusted-types-2.0.7.tgz",
+      "integrity": "sha512-ScaPdn1dQczgbl0QFTeTOmVHFULt394XJgOQNoyVhZ6r2vLnMLJfBPd53SB52T/3G36VI1/g2MZaX0cwDuXsfw==",
+      "optional": true
+    },
     "node_modules/@types/unist": {
       "version": "3.0.3",
       "resolved": "https://registry.npmjs.org/@types/unist/-/unist-3.0.3.tgz",
@@ -3172,6 +3189,14 @@
         "node": ">=0.10.0"
       }
     },
+    "node_modules/dompurify": {
+      "version": "3.4.14",
+      "resolved": "https://registry.npmjs.org/dompurify/-/dompurify-3.4.14.tgz",
+      "integrity": "sha512-dVoH9z+MY+C9IilgGCk3YfFqjLi3fChm2OiKJMzh6axrJ5qwxqWaZamgmHrpv22CN/KdbZJuGEGgfQoL00LTdg==",
+      "optionalDependencies": {
+        "@types/trusted-types": "^2.0.7"
+      }
+    },
     "node_modules/dotenv": {
       "version": "16.6.1",
       "resolved": "https://registry.npmjs.org/dotenv/-/dotenv-16.6.1.tgz",