fix(lint): use eslint-config-next flat config

eslint-config-next 16.3.5 ships flat configs; feeding them through
FlatCompat wrapped the plugins and crashed lint with a circular-structure
JSON error. Import the flat config directly and drop @eslint/eslintrc.

eslint.config.js

@@ -1,17 +1,13 @@
-import { FlatCompat } from "@eslint/eslintrc";
 import tseslint from "typescript-eslint";
 // @ts-ignore -- no types for this plugin
 import drizzle from "eslint-plugin-drizzle";
-
-const compat = new FlatCompat({
-  baseDirectory: import.meta.dirname,
-});
+import nextVitals from "eslint-config-next/core-web-vitals";
 
 export default tseslint.config(
   {
     ignores: [".next"],
   },
-  ...compat.extends("next/core-web-vitals"),
+  ...nextVitals,
   {
     files: ["**/*.ts", "**/*.tsx"],
     plugins: {
@@ -58,4 +54,4 @@ export default tseslint.config(
       },
     },
   },
-);
+);