ci: give the package a lint gate, and put typecheck in verify

eslint.config.mjs

@@ -0,0 +1,44 @@
+// Flat config (ESLint 9). Deliberately close to the recommended presets: this
+// package is ~1k lines of library code, and a bespoke rule set would be a
+// second opinion to maintain for no benefit. The floor is "lint runs and can
+// fail", not "lint encodes taste".
+import js from '@eslint/js'
+import globals from 'globals'
+import reactHooks from 'eslint-plugin-react-hooks'
+import tseslint from 'typescript-eslint'
+
+export default tseslint.config(
+  {
+    // dist/ is generated by `tsc`; examples/ is a standalone Next.js app with
+    // its own toolchain and is not part of this package's published `files`.
+    ignores: ['dist/**', 'examples/**', 'node_modules/**'],
+  },
+  js.configs.recommended,
+  ...tseslint.configs.recommended,
+  {
+    files: ['**/*.ts'],
+    languageOptions: { globals: globals.node },
+    rules: {
+      // The public API intentionally accepts arbitrary user-supplied form
+      // shapes, so a handful of `any`s are load-bearing rather than lazy.
+      // Warn, so they stay visible without failing the gate on existing code.
+      '@typescript-eslint/no-explicit-any': 'warn',
+    },
+  },
+  {
+    // src/react.ts exports a hook, and already carries an
+    // `eslint-disable-next-line react-hooks/exhaustive-deps`. Without the
+    // plugin installed that directive is itself an ESLint error ("rule not
+    // found") — the comment was writing a cheque the config could not cash.
+    // Installing it makes the suppression meaningful AND lints the hook.
+    files: ['src/react.ts'],
+    plugins: { 'react-hooks': reactHooks },
+    rules: reactHooks.configs.recommended.rules,
+  },
+  {
+    // Tests and scripts are plain Node under `node --test`. `Request`/`URL`
+    // are Node 18+ globals, so they need the node globals set to resolve.
+    files: ['test/**/*.js', 'scripts/**/*.{js,mjs}'],
+    languageOptions: { globals: { ...globals.node, ...globals.nodeBuiltin } },
+  },
+)