Add test file exception for prefer-arrow-callback rule and update Copilot instructions

Co-authored-by: kraenhansen <1243959+kraenhansen@users.noreply.github.com>

Author: Copilot

.github/copilot-instructions.md

@@ -61,7 +61,7 @@ npm run bootstrap           # Build native components (weak-node-api, examples)
 **Function Style**:
 - Prefer `export function` over `export const fn =`
 - Use async/await consistently for asynchronous operations
-- Prefer arrow functions for callbacks and inline functions
+- Prefer arrow functions for callbacks and inline functions (except in tests where `describe` and `it` use regular functions)
 
 **Error Handling**:
 - Prefer `assert()` from `node:assert/strict` over throwing errors directly

eslint.config.js

@@ -1,6 +1,6 @@
 // @ts-check
 
-import { globalIgnores } from "eslint/config";
+// import { globalIgnores } from "eslint/config";
 import globals from "globals";
 import eslint from "@eslint/js";
 import tseslint from "typescript-eslint";
@@ -10,7 +10,8 @@ import nodePlugin from "eslint-plugin-n";
 import unusedImports from "eslint-plugin-unused-imports";
 
 export default tseslint.config(
-  globalIgnores([
+  {
+    ignores: [
     "**/dist/**",
     "**/build/**",
     "apps/test-app/ios/**",
@@ -23,7 +24,8 @@ export default tseslint.config(
     "packages/node-tests/tests/**",
     "packages/node-tests/*.generated.js",
     "packages/node-tests/*.generated.d.ts",
-  ]),
+  ],
+  },
   eslint.configs.recommended,
   tseslint.configs.recommendedTypeChecked,
   {
@@ -140,4 +142,11 @@ export default tseslint.config(
       },
     },
   },
+  {
+    // Exception for test files: allow regular functions in describe() and it() callbacks
+    files: ["**/*.test.ts", "**/*.spec.ts"],
+    rules: {
+      "prefer-arrow-callback": "off",
+    },
+  },
 );