feat: migrate ESLint to flat config (#201)

Author: DerekRoberts

backend/eslint.config.mjs

@@ -0,0 +1,30 @@
+import baseConfig, { baseIgnores } from "../eslint-base.config.mjs";
+import globals from "globals";
+import tsParser from "@typescript-eslint/parser";
+
+export default [
+  ...baseConfig,
+  {
+    ignores: [
+      ...baseIgnores,
+      "**/*.config.*",
+      "**/prisma/**",
+    ],
+  },
+  {
+    languageOptions: {
+      globals: {
+        ...globals.node,
+      },
+
+      parser: tsParser,
+      ecmaVersion: "latest",
+      sourceType: "module",
+
+      parserOptions: {
+        project: ["./tsconfig.json"],
+      },
+    },
+  },
+];
+