infra: add eslint and handle floating promises

eslint.config.js

@@ -0,0 +1,43 @@
+import pluginJs from "@eslint/js";
+import configPrettier from "eslint-config-prettier";
+import pluginReact from "eslint-plugin-react";
+import pluginReactHooks from "eslint-plugin-react-hooks";
+import pluginTypescript from "typescript-eslint";
+
+for (const config of pluginTypescript.configs.recommendedTypeChecked) {
+  config.files = ["**/*.{ts,tsx,mts,cts}"]; // ensure config only targets TypeScript files
+}
+
+/** @type {import('eslint').Linter.Config[]} */
+export default [
+  { ignores: ["dist/", "out/"] },
+  pluginJs.configs.recommended,
+  pluginReact.configs.flat.recommended,
+  pluginReact.configs.flat["jsx-runtime"],
+  { settings: { react: { version: "detect" } } },
+  { plugins: { "react-hooks": pluginReactHooks } },
+  {
+    rules: {
+      "no-undef": "off",
+      "no-unused-vars": [
+        "error",
+        { argsIgnorePattern: "^_", varsIgnorePattern: "^_" },
+      ],
+      "react/prop-types": "off",
+      "react-hooks/rules-of-hooks": "error",
+      "react-hooks/exhaustive-deps": "error",
+    },
+  },
+  ...pluginTypescript.configs.recommendedTypeChecked,
+  { languageOptions: { parserOptions: { projectService: true } } },
+  {
+    files: ["**/*.{ts,tsx,mts,cts}"],
+    rules: {
+      "@typescript-eslint/no-unused-vars": [
+        "error",
+        { argsIgnorePattern: "^_", varsIgnorePattern: "^_" },
+      ],
+    },
+  },
+  configPrettier,
+];