fix(security): sanitize HTML content to prevent XSS attacks

Add DOMPurify to sanitize user-generated HTML in the preferences
section before rendering with dangerouslySetInnerHTML.

package-lock.json

@@ -17,6 +17,7 @@
         "axios": "^1.13.2",
         "better-sqlite3": "^12.4.1",
         "cheerio": "^1.1.2",
+        "dompurify": "^3.3.1",
         "drizzle-orm": "^0.45.1",
         "jsonwebtoken": "^9.0.2",
         "lexical": "^0.39.0",
@@ -28,6 +29,7 @@
       "devDependencies": {
         "@tailwindcss/postcss": "^4",
         "@types/better-sqlite3": "^7.6.13",
+        "@types/dompurify": "^3.0.5",
         "@types/jsonwebtoken": "^9.0.10",
         "@types/node": "^20",
         "@types/react": "^19",
@@ -2358,6 +2360,16 @@
         "@types/node": "*"
       }
     },
+    "node_modules/@types/dompurify": {
+      "version": "3.0.5",
+      "resolved": "https://registry.npmjs.org/@types/dompurify/-/dompurify-3.0.5.tgz",
+      "integrity": "sha512-1Wg0g3BtQF7sSb27fJQAKck1HECM6zV1EB66j8JH9i3LCjYabJa0FSdiSgsD5K/RbrsR0SiraKacLB+T8ZVYAg==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "@types/trusted-types": "*"
+      }
+    },
     "node_modules/@types/estree": {
       "version": "1.0.8",
       "resolved": "https://registry.npmjs.org/@types/estree/-/estree-1.0.8.tgz",
@@ -2427,6 +2439,13 @@
         "@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==",
+      "devOptional": true,
+      "license": "MIT"
+    },
     "node_modules/@typescript-eslint/eslint-plugin": {
       "version": "8.52.0",
       "resolved": "https://registry.npmjs.org/@typescript-eslint/eslint-plugin/-/eslint-plugin-8.52.0.tgz",
@@ -3905,6 +3924,15 @@
         "url": "https://github.com/fb55/domhandler?sponsor=1"
       }
     },
+    "node_modules/dompurify": {
+      "version": "3.3.1",
+      "resolved": "https://registry.npmjs.org/dompurify/-/dompurify-3.3.1.tgz",
+      "integrity": "sha512-qkdCKzLNtrgPFP1Vo+98FRzJnBRGe4ffyCea9IwHB1fyxPOeNTHpLKYGd4Uk9xvNoH0ZoOjwZxNptyMwqrId1Q==",
+      "license": "(MPL-2.0 OR Apache-2.0)",
+      "optionalDependencies": {
+        "@types/trusted-types": "^2.0.7"
+      }
+    },
     "node_modules/domutils": {
       "version": "3.2.2",
       "resolved": "https://registry.npmjs.org/domutils/-/domutils-3.2.2.tgz",