Upgrade ESLint to version 9 (#6)

* chore: upgrade ESLint to version 9

- Upgrade eslint from ^8.57.0 to ^9.39.1
- Migrate from .eslintrc.js to flat config (eslint.config.mjs)
- Add required ESLint v9 dependencies (@eslint/js, typescript-eslint)
- Add eslint-formatter-unix package for unix format support
- Remove unused eslint-disable directive from memoize.ts
- Verify all tests and linting pass successfully

* refactor: use globals package and upgrade eslint-related packages

- Install globals package and refactor eslint.config.mjs to use it
- Replace manual globals definition with globals.node and globals.es2021
- Upgrade eslint-config-prettier: 9.1.0 → 10.1.8
- Upgrade eslint-plugin-prettier: 5.1.3 → 5.5.4
- Upgrade eslint-plugin-simple-import-sort: 10.0.0 → 12.1.1
- Upgrade eslint-plugin-tsdoc: 0.2.17 → 0.4.0
- Upgrade prettier: 3.3.2 → 3.6.2
- Verify all tests and linting pass successfully

---------

Co-authored-by: Claude <noreply@anthropic.com>

Author: jmlweb

.eslintrc.js

@@ -0,0 +1,45 @@
+import eslint from '@eslint/js';
+import prettierConfig from 'eslint-config-prettier';
+import prettierPlugin from 'eslint-plugin-prettier';
+import simpleImportSort from 'eslint-plugin-simple-import-sort';
+import tsdoc from 'eslint-plugin-tsdoc';
+import globals from 'globals';
+import tseslint from 'typescript-eslint';
+
+export default [
+  // Base ESLint recommended rules
+  eslint.configs.recommended,
+
+  // TypeScript ESLint recommended rules
+  ...tseslint.configs.recommended,
+
+  // Prettier config (disables conflicting rules)
+  prettierConfig,
+
+  // Main configuration
+  {
+    files: ['**/*.ts', '**/*.tsx'],
+    plugins: {
+      '@typescript-eslint': tseslint.plugin,
+      'simple-import-sort': simpleImportSort,
+      'tsdoc': tsdoc,
+      'prettier': prettierPlugin,
+    },
+    languageOptions: {
+      parser: tseslint.parser,
+      parserOptions: {
+        project: './tsconfig.json',
+      },
+      globals: {
+        ...globals.node,
+        ...globals.es2021,
+      },
+    },
+    rules: {
+      'prettier/prettier': 'error',
+      'simple-import-sort/imports': 'error',
+      'simple-import-sort/exports': 'error',
+      'tsdoc/syntax': 'warn',
+    },
+  },
+];

eslint.config.mjs

@@ -53,6 +53,7 @@
   },
   "devDependencies": {
     "@commitlint/config-conventional": "^20.0.0",
+    "@eslint/js": "^9.39.1",
     "@mxssfd/typedoc-theme": "^1.1.3",
     "@semantic-release/git": "^10.0.1",
     "@size-limit/esbuild": "^11.2.0",
@@ -62,21 +63,24 @@
     "@typescript-eslint/eslint-plugin": "^8.0.0",
     "@typescript-eslint/parser": "^8.0.0",
     "commitlint": "^20.1.0",
-    "eslint": "^8.57.0",
-    "eslint-config-prettier": "^9.1.0",
-    "eslint-plugin-prettier": "^5.1.1",
-    "eslint-plugin-simple-import-sort": "^10.0.0",
-    "eslint-plugin-tsdoc": "^0.2.17",
+    "eslint": "^9.39.1",
+    "eslint-config-prettier": "^10.1.8",
+    "eslint-formatter-unix": "^9.0.1",
+    "eslint-plugin-prettier": "^5.5.4",
+    "eslint-plugin-simple-import-sort": "^12.1.1",
+    "eslint-plugin-tsdoc": "^0.4.0",
+    "globals": "^16.5.0",
     "husky": "^9.1.7",
     "jest": "^29.7.0",
     "lint-staged": "^16.2.6",
-    "prettier": "^3.3.0",
+    "prettier": "^3.6.2",
     "semantic-release": "^24.0.0",
     "size-limit": "^11.2.0",
     "ts-jest": "^29.2.0",
     "tsup": "^8.3.0",
     "type-coverage": "^2.29.7",
     "typedoc": "^0.27.0",
-    "typescript": "^5.6.3"
+    "typescript": "^5.6.3",
+    "typescript-eslint": "^8.46.3"
   }
 }