chore: update Next.js version to 15.2.6 (#2591)

Updating next.js to patch CVE-2025-66478
https://nextjs.org/blog/CVE-2025-66478#fixed-versions

Updated the minimum to cause the least disruption 

---

### Changes are visible to end-users: yes/no

no

### Test plan

<!-- Delete any which do not apply -->

- Covered by existing test cases

Author: scottshuffler

.aspect/rules/external_repository_action_cache/npm_translate_lock_LTE4Nzc1MDcwNjU=

@@ -10,7 +10,7 @@ examples/linked_empty_node_modules/package.json=-1039372825
 examples/linked_lib/package.json=-1249214784
 examples/linked_pkg/package.json=344249322
 examples/macro/package.json=857146175
-examples/nextjs/package.json=886845923
+examples/nextjs/package.json=-1479189147
 examples/npm_deps/package.json=-929156430
 examples/npm_deps/patches/[email protected]=-442666336
 examples/npm_package/libs/lib_a/package.json=-1377103079
@@ -33,5 +33,5 @@ npm/private/test/vendored/is-odd/package.json=1041695223
 npm/private/test/vendored/lodash-4.17.21.tgz=-1206623349
 npm/private/test/vendored/semver-max/package.json=578664053
 package.json=-1957263621
-pnpm-lock.yaml=-1112726679
+pnpm-lock.yaml=1902914053
 pnpm-workspace.yaml=-1336981113

examples/nextjs/package.json

@@ -11,7 +11,7 @@
     "dependencies": {
         "react": "^19.1.0",
         "react-dom": "^19.1.0",
-        "next": "15.2.4"
+        "next": "15.2.6"
     },
     "devDependencies": {
         "@tailwindcss/postcss": "4.1.0",