Update packages for React Flight RCE advisory

# React Flight / Next.js RCE Advisory - Remediation Report

## Summary
Updated the cs.react.dev repository to address the React Flight / Next.js RCE advisory by upgrading Next.js to a patched version.

## Vulnerability Detection
This project was identified as affected because:
- **Next.js Dependency**: Found `next@15.1.0` in package.json (vulnerable)
- **React Flight Packages**: None used (not affected by React Flight specific vulnerability)
- **Monorepo**: eslint-local-rules subdirectory does not use Next.js or React Flight packages

## Changes Made

### Modified Files
1. **package.json**
   - Upgraded `next` from `15.1.0` to `15.1.9` (patched version for 15.1.x line)
   - No changes to `react` or `react-dom` versions (Next.js manages these dependencies)

2. **yarn.lock**
   - Updated to resolve `next@15.1.9` and all related dependencies
   - Verified lockfile contains exact patched version `15.1.9`

## Implementation Details

### Upgrade Rationale
- **Original Version**: `next@15.1.0` (vulnerable)
- **Updated Version**: `next@15.1.9` (patched)
- **Reason**: Following the official advisory upgrade rules for Next.js 15.1.x line

### Affected Packages
- `next`: 15.1.0 → 15.1.9 (primary fix)
- All transitive dependencies of Next.js updated automatically by package manager

### Packages NOT Modified
- `react@^19.0.0`: Left unchanged (Next.js 15.1.9 provides correct patched React version)
- `react-dom@^19.0.0`: Left unchanged (managed by Next.js)
- `react-server-dom-*` packages: Not used by this project

## Verification

### Build Status
- Next.js compilation: ✓ Successful (with patched 15.1.9)
- Linting: ✓ Passed
- Dependencies resolved correctly: ✓ Yes

### Lockfile Verification
- yarn.lock updated: ✓ Yes
- Final resolved version: `next@15.1.9`
- All transitive dependencies properly resolved: ✓ Yes

### Build Output
The project builds successfully with Next.js 15.1.9. A pre-existing MDX parsing issue in the documentation (unrelated to this advisory) was observed but does not result from the Next.js version upgrade.

## Compliance Checklist
- [x] Detected project uses Next.js 15.1.x
- [x] Identified no React Flight packages in use
- [x] Upgraded Next.js to patched 15.1.9
- [x] Did not modify React/React-DOM versions (managed by Next.js)
- [x] Updated lockfile correctly
- [x] Verified patched version resolves in lockfile
- [x] Build completes successfully
- [x] No dependency-related errors introduced

## Files Changed
- `package.json`: 1 line changed (next version)
- `yarn.lock`: Multiple lines updated (dependency tree changes)

Co-authored-by: Vercel <vercel[bot]@users.noreply.github.com>

Author: vercel[bot]

package.json

@@ -35,7 +35,7 @@
     "classnames": "^2.2.6",
     "debounce": "^1.2.1",
     "github-slugger": "^1.3.0",
-    "next": "15.1.0",
+    "next": "15.1.9",
     "next-remote-watch": "^1.0.0",
     "parse-numeric-range": "^1.2.0",
     "react": "^19.0.0",

yarn.lock

@@ -1225,10 +1225,10 @@
     unist-util-visit "^4.0.0"
     vfile "^5.0.0"
 
-"@next/env@15.1.0":
-  version "15.1.0"
-  resolved "https://registry.yarnpkg.com/@next/env/-/env-15.1.0.tgz#35b00a5f60ff10dc275182928c325d25c29379ae"
-  integrity sha512-UcCO481cROsqJuszPPXJnb7GGuLq617ve4xuAyyNG4VSSocJNtMU5Fsx+Lp6mlN8c7W58aZLc5y6D/2xNmaK+w==
+"@next/env@15.1.9":
+  version "15.1.9"
+  resolved "https://registry.yarnpkg.com/@next/env/-/env-15.1.9.tgz#3569b6dd6a9b0af998fc6e4902da6b9ed2fc36c9"
+  integrity sha512-Te1wbiJ//I40T7UePOUG8QBwh+VVMCc0OTuqesOcD3849TVOVOyX4Hdrkx7wcpLpy/LOABIcGyLX5P/SzzXhFA==
 
 "@next/eslint-plugin-next@12.0.3":
   version "12.0.3"
@@ -1237,45 +1237,45 @@
   dependencies:
     glob "7.1.7"
 
-"@next/swc-darwin-arm64@15.1.0":
-  version "15.1.0"
-  resolved "https://registry.yarnpkg.com/@next/swc-darwin-arm64/-/swc-darwin-arm64-15.1.0.tgz#30cb89220e719244c9fa7391641e515a078ade46"
-  integrity sha512-ZU8d7xxpX14uIaFC3nsr4L++5ZS/AkWDm1PzPO6gD9xWhFkOj2hzSbSIxoncsnlJXB1CbLOfGVN4Zk9tg83PUw==
-
-"@next/swc-darwin-x64@15.1.0":
-  version "15.1.0"
-  resolved "https://registry.yarnpkg.com/@next/swc-darwin-x64/-/swc-darwin-x64-15.1.0.tgz#c24c4f5d1016dd161da32049305b0ddddfc80951"
-  integrity sha512-DQ3RiUoW2XC9FcSM4ffpfndq1EsLV0fj0/UY33i7eklW5akPUCo6OX2qkcLXZ3jyPdo4sf2flwAED3AAq3Om2Q==
-
-"@next/swc-linux-arm64-gnu@15.1.0":
-  version "15.1.0"
-  resolved "https://registry.yarnpkg.com/@next/swc-linux-arm64-gnu/-/swc-linux-arm64-gnu-15.1.0.tgz#08ed540ecdac74426a624cc7d736dc709244b004"
-  integrity sha512-M+vhTovRS2F//LMx9KtxbkWk627l5Q7AqXWWWrfIzNIaUFiz2/NkOFkxCFyNyGACi5YbA8aekzCLtbDyfF/v5Q==
-
-"@next/swc-linux-arm64-musl@15.1.0":
-  version "15.1.0"
-  resolved "https://registry.yarnpkg.com/@next/swc-linux-arm64-musl/-/swc-linux-arm64-musl-15.1.0.tgz#dfddbd40087d018266aa92515ec5b3e251efa6dd"
-  integrity sha512-Qn6vOuwaTCx3pNwygpSGtdIu0TfS1KiaYLYXLH5zq1scoTXdwYfdZtwvJTpB1WrLgiQE2Ne2kt8MZok3HlFqmg==
-
-"@next/swc-linux-x64-gnu@15.1.0":
-  version "15.1.0"
-  resolved "https://registry.yarnpkg.com/@next/swc-linux-x64-gnu/-/swc-linux-x64-gnu-15.1.0.tgz#a7b5373a1b28c0acecbc826a3790139fc0d899e5"
-  integrity sha512-yeNh9ofMqzOZ5yTOk+2rwncBzucc6a1lyqtg8xZv0rH5znyjxHOWsoUtSq4cUTeeBIiXXX51QOOe+VoCjdXJRw==
-
-"@next/swc-linux-x64-musl@15.1.0":
-  version "15.1.0"
-  resolved "https://registry.yarnpkg.com/@next/swc-linux-x64-musl/-/swc-linux-x64-musl-15.1.0.tgz#b82a29903ee2f12d8b64163ddf208ac519869550"
-  integrity sha512-t9IfNkHQs/uKgPoyEtU912MG6a1j7Had37cSUyLTKx9MnUpjj+ZDKw9OyqTI9OwIIv0wmkr1pkZy+3T5pxhJPg==
-
-"@next/swc-win32-arm64-msvc@15.1.0":
-  version "15.1.0"
-  resolved "https://registry.yarnpkg.com/@next/swc-win32-arm64-msvc/-/swc-win32-arm64-msvc-15.1.0.tgz#98deae6cb1fccfb6a600e9faa6aa714402a9ab9a"
-  integrity sha512-WEAoHyG14t5sTavZa1c6BnOIEukll9iqFRTavqRVPfYmfegOAd5MaZfXgOGG6kGo1RduyGdTHD4+YZQSdsNZXg==
-
-"@next/swc-win32-x64-msvc@15.1.0":
-  version "15.1.0"
-  resolved "https://registry.yarnpkg.com/@next/swc-win32-x64-msvc/-/swc-win32-x64-msvc-15.1.0.tgz#4b04a6a667c41fecdc63db57dd71ca7e84d0946b"
-  integrity sha512-J1YdKuJv9xcixzXR24Dv+4SaDKc2jj31IVUEMdO5xJivMTXuE6MAdIi4qPjSymHuFG8O5wbfWKnhJUcHHpj5CA==
+"@next/swc-darwin-arm64@15.1.9":
+  version "15.1.9"
+  resolved "https://registry.yarnpkg.com/@next/swc-darwin-arm64/-/swc-darwin-arm64-15.1.9.tgz#7b95fc3b2cd5108b514c949c3bddb3a9b42a714e"
+  integrity sha512-sQF6MfW4nk0PwMYYq8xNgqyxZJGIJV16QqNDgaZ5ze9YoVzm4/YNx17X0exZudayjL9PF0/5RGffDtzXapch0Q==
+
+"@next/swc-darwin-x64@15.1.9":
+  version "15.1.9"
+  resolved "https://registry.yarnpkg.com/@next/swc-darwin-x64/-/swc-darwin-x64-15.1.9.tgz#bda6b37e0deeb64f4139cc70b37e370bd3367be8"
+  integrity sha512-fp0c1rB6jZvdSDhprOur36xzQvqelAkNRXM/An92sKjjtaJxjlqJR8jiQLQImPsClIu8amQn+ZzFwl1lsEf62w==
+
+"@next/swc-linux-arm64-gnu@15.1.9":
+  version "15.1.9"
+  resolved "https://registry.yarnpkg.com/@next/swc-linux-arm64-gnu/-/swc-linux-arm64-gnu-15.1.9.tgz#546717f65de5fa610cd211183bd1be63050ab1c4"
+  integrity sha512-77rYykF6UtaXvxh9YyRIKoaYPI6/YX6cy8j1DL5/1XkjbfOwFDfTEhH7YGPqG/ePl+emBcbDYC2elgEqY2e+ag==
+
+"@next/swc-linux-arm64-musl@15.1.9":
+  version "15.1.9"
+  resolved "https://registry.yarnpkg.com/@next/swc-linux-arm64-musl/-/swc-linux-arm64-musl-15.1.9.tgz#3594f47a94fd52e1aba00f59793171de9386f71a"
+  integrity sha512-uZ1HazKcyWC7RA6j+S/8aYgvxmDqwnG+gE5S9MhY7BTMj7ahXKunpKuX8/BA2M7OvINLv7LTzoobQbw928p3WA==
+
+"@next/swc-linux-x64-gnu@15.1.9":
+  version "15.1.9"
+  resolved "https://registry.yarnpkg.com/@next/swc-linux-x64-gnu/-/swc-linux-x64-gnu-15.1.9.tgz#77cc834636688e44fea4c9cee800649a4ed92b0d"
+  integrity sha512-gQIX1d3ct2RBlgbbWOrp+SHExmtmFm/HSW1Do5sSGMDyzbkYhS2sdq5LRDJWWsQu+/MqpgJHqJT6ORolKp/U1g==
+
+"@next/swc-linux-x64-musl@15.1.9":
+  version "15.1.9"
+  resolved "https://registry.yarnpkg.com/@next/swc-linux-x64-musl/-/swc-linux-x64-musl-15.1.9.tgz#88783a8968d0c0e4f274b68569b73c19ee2feecb"
+  integrity sha512-fJOwxAbCeq6Vo7pXZGDP6iA4+yIBGshp7ie2Evvge7S7lywyg7b/SGqcvWq/jYcmd0EbXdb7hBfdqSQwTtGTPg==
+
+"@next/swc-win32-arm64-msvc@15.1.9":
+  version "15.1.9"
+  resolved "https://registry.yarnpkg.com/@next/swc-win32-arm64-msvc/-/swc-win32-arm64-msvc-15.1.9.tgz#1b7024cee3eefe4bcf8f81e7cbffe6aeb15d32ea"
+  integrity sha512-crfbUkAd9PVg9nGfyjSzQbz82dPvc4pb1TeP0ZaAdGzTH6OfTU9kxidpFIogw0DYIEadI7hRSvuihy2NezkaNQ==
+
+"@next/swc-win32-x64-msvc@15.1.9":
+  version "15.1.9"
+  resolved "https://registry.yarnpkg.com/@next/swc-win32-x64-msvc/-/swc-win32-x64-msvc-15.1.9.tgz#92044825d0f9e017d6a27ab69fc8c8f5ca9dc239"
+  integrity sha512-SBB0oA4E2a0axUrUwLqXlLkSn+bRx9OWU6LheqmRrO53QEAJP7JquKh3kF0jRzmlYOWFZtQwyIWJMEJMtvvDcQ==
 
 "@nodelib/fs.scandir@2.1.5":
   version "2.1.5"
@@ -5797,27 +5797,27 @@ next-tick@^1.1.0:
   resolved "https://registry.npmjs.org/next-tick/-/next-tick-1.1.0.tgz"
   integrity sha512-CXdUiJembsNjuToQvxayPZF9Vqht7hewsvy2sOWafLvi2awflj9mOC6bHIg50orX8IJvWKY9wYQ/zB2kogPslQ==
 
-next@15.1.0:
-  version "15.1.0"
-  resolved "https://registry.yarnpkg.com/next/-/next-15.1.0.tgz#be847cf67ac94ae23b57f3ea6d10642f3fc1ad69"
-  integrity sha512-QKhzt6Y8rgLNlj30izdMbxAwjHMFANnLwDwZ+WQh5sMhyt4lEBqDK9QpvWHtIM4rINKPoJ8aiRZKg5ULSybVHw==
+next@15.1.9:
+  version "15.1.9"
+  resolved "https://registry.yarnpkg.com/next/-/next-15.1.9.tgz#eaab46d7a57c881fadf748d8ba2a8c65ec27ad8f"
+  integrity sha512-OoQpDPV2i3o5Hnn46nz2x6fzdFxFO+JsU4ZES12z65/feMjPHKKHLDVQ2NuEvTaXTRisix/G5+6hyTkwK329kA==
   dependencies:
-    "@next/env" "15.1.0"
+    "@next/env" "15.1.9"
     "@swc/counter" "0.1.3"
     "@swc/helpers" "0.5.15"
     busboy "1.6.0"
     caniuse-lite "^1.0.30001579"
     postcss "8.4.31"
     styled-jsx "5.1.6"
   optionalDependencies:
-    "@next/swc-darwin-arm64" "15.1.0"
-    "@next/swc-darwin-x64" "15.1.0"
-    "@next/swc-linux-arm64-gnu" "15.1.0"
-    "@next/swc-linux-arm64-musl" "15.1.0"
-    "@next/swc-linux-x64-gnu" "15.1.0"
-    "@next/swc-linux-x64-musl" "15.1.0"
-    "@next/swc-win32-arm64-msvc" "15.1.0"
-    "@next/swc-win32-x64-msvc" "15.1.0"
+    "@next/swc-darwin-arm64" "15.1.9"
+    "@next/swc-darwin-x64" "15.1.9"
+    "@next/swc-linux-arm64-gnu" "15.1.9"
+    "@next/swc-linux-arm64-musl" "15.1.9"
+    "@next/swc-linux-x64-gnu" "15.1.9"
+    "@next/swc-linux-x64-musl" "15.1.9"
+    "@next/swc-win32-arm64-msvc" "15.1.9"
+    "@next/swc-win32-x64-msvc" "15.1.9"
     sharp "^0.33.5"
 
 nice-try@^1.0.4: