diff --git a/ui/package-lock.json b/ui/package-lock.json
index 0496b3c92149c3e45e028294939317a706f84168..e7ca9f01ec66822d154f885f01deadaf112f9913 100644
--- a/ui/package-lock.json
+++ b/ui/package-lock.json
@@ -15,6 +15,7 @@
       "devDependencies": {
         "@eslint/js": "^9.35.0",
         "@playwright/test": "^1.40.0",
+        "@types/node": "^22.0.0",
         "@types/react": "^18.2.0",
         "@types/react-dom": "^18.2.0",
         "@typescript-eslint/eslint-plugin": "^8.43.0",
@@ -777,6 +778,16 @@
       "dev": true,
       "license": "MIT"
     },
+    "node_modules/@types/node": {
+      "version": "22.19.3",
+      "resolved": "https://registry.npmjs.org/@types/node/-/node-22.19.3.tgz",
+      "integrity": "sha512-1N9SBnWYOJTrNZCdh/yJE+t910Y128BoyY+zBLWhL3r0TYzlTmFdXrPwHL9DyFZmlEXNQQolTZh3KHV31QDhyA==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "undici-types": "~6.21.0"
+      }
+    },
     "node_modules/@types/prop-types": {
       "version": "15.7.15",
       "resolved": "https://registry.npmjs.org/@types/prop-types/-/prop-types-15.7.15.tgz",
@@ -790,6 +801,7 @@
       "integrity": "sha512-RFA/bURkcKzx/X9oumPG9Vp3D3JUgus/d0b67KB0t5S/raciymilkOa66olh78MUI92QLbEJevO7rvqU/kjwKA==",
       "dev": true,
       "license": "MIT",
+      "peer": true,
       "dependencies": {
         "@types/prop-types": "*",
         "csstype": "^3.0.2"
@@ -841,6 +853,7 @@
       "integrity": "sha512-n1H6IcDhmmUEG7TNVSspGmiHHutt7iVKtZwRppD7e04wha5MrkV1h3pti9xQLcCMt6YWsncpoT0HMjkH1FNwWQ==",
       "dev": true,
       "license": "MIT",
+      "peer": true,
       "dependencies": {
         "@typescript-eslint/scope-manager": "8.46.0",
         "@typescript-eslint/types": "8.46.0",
@@ -1046,6 +1059,7 @@
       "integrity": "sha512-NZyJarBfL7nWwIq+FDL6Zp/yHEhePMNnnJ0y3qfieCrmNvYct8uvtiV41UvlSe6apAfk0fY1FbWx+NwfmpvtTg==",
       "dev": true,
       "license": "MIT",
+      "peer": true,
       "bin": {
         "acorn": "bin/acorn"
       },
@@ -1801,6 +1815,7 @@
       "integrity": "sha512-XyLmROnACWqSxiGYArdef1fItQd47weqB7iwtfr9JHwRrqIXZdcFMvvEcL9xHCmL0SNsOvF0c42lWyM1U5dgig==",
       "dev": true,
       "license": "MIT",
+      "peer": true,
       "dependencies": {
         "@eslint-community/eslint-utils": "^4.8.0",
         "@eslint-community/regexpp": "^4.12.1",
@@ -3528,6 +3543,7 @@
       "resolved": "https://registry.npmjs.org/react/-/react-18.3.1.tgz",
       "integrity": "sha512-wS+hAgJShR0KhEvPJArfuPVN1+Hz1t0Y6n5jLrGQbkb4urgPE/0Rve+1kMB1v/oWgHgm4WIcV+i7F2pTVj+2iQ==",
       "license": "MIT",
+      "peer": true,
       "dependencies": {
         "loose-envify": "^1.1.0"
       },
@@ -4612,6 +4628,7 @@
       "integrity": "sha512-jl1vZzPDinLr9eUt3J/t7V6FgNEw9QjvBPdysz9KfQDD41fQrC2Y4vKQdiaUpFT4bXlb1RHhLpp8wtm6M5TgSw==",
       "dev": true,
       "license": "Apache-2.0",
+      "peer": true,
       "bin": {
         "tsc": "bin/tsc",
         "tsserver": "bin/tsserver"
@@ -4663,6 +4680,13 @@
         "url": "https://github.com/sponsors/ljharb"
       }
     },
+    "node_modules/undici-types": {
+      "version": "6.21.0",
+      "resolved": "https://registry.npmjs.org/undici-types/-/undici-types-6.21.0.tgz",
+      "integrity": "sha512-iwDZqg0QAGrg9Rav5H4n0M64c3mkR59cJ6wQp+7C4nI0gsmExaedaYLNO44eT4AtBBwjbTiGPMlt2Md0T9H9JQ==",
+      "dev": true,
+      "license": "MIT"
+    },
     "node_modules/uri-js": {
       "version": "4.4.1",
       "resolved": "https://registry.npmjs.org/uri-js/-/uri-js-4.4.1.tgz",
diff --git a/ui/package.json b/ui/package.json
index 8ffb417236975058a1cc7d8ba501fd5e629747f0..c5138965ee9e56cb50b083cdf44cdcbbde11dcf4 100644
--- a/ui/package.json
+++ b/ui/package.json
@@ -26,6 +26,7 @@
   },
   "devDependencies": {
     "@eslint/js": "^9.35.0",
+    "@types/node": "^22.0.0",
     "@playwright/test": "^1.40.0",
     "@types/react": "^18.2.0",
     "@types/react-dom": "^18.2.0",
diff --git a/ui/src/components/Message.tsx b/ui/src/components/Message.tsx
index 41207bc7f92a8b46dab13e6e879e4a95522276ef..566d1221e054b1a7dbaaa2f3890e6473ffd4b8be 100644
--- a/ui/src/components/Message.tsx
+++ b/ui/src/components/Message.tsx
@@ -112,7 +112,7 @@ function Message({ message, onOpenDiffViewer }: MessageProps) {
   // Context menu state
   const [contextMenu, setContextMenu] = useState<{ x: number; y: number } | null>(null);
   const [showUsageModal, setShowUsageModal] = useState(false);
-  const [longPressTimer, setLongPressTimer] = useState<number | null>(null);
+  const [longPressTimer, setLongPressTimer] = useState<ReturnType<typeof setTimeout> | null>(null);
   const messageRef = useRef<HTMLDivElement | null>(null);
 
   // Parse usage data if available (only for agent messages)