feat(eslint): add eslint flat config

.eslint/typescript.ts

@@ -0,0 +1,44 @@
+import type { Linter } from "eslint";
+import { typescriptFiles } from "./shared";
+
+export function createTypescriptConfig(tsConfigPath: string): Linter.Config {
+  return {
+    name: "eslint/typescript",
+    files: typescriptFiles,
+    languageOptions: {
+      parserOptions: {
+        ecmaVersion: "latest",
+        sourceType: "module",
+        ecmaFeatures: {
+          jsx: true,
+        },
+        project: tsConfigPath,
+        tsconfigRootDir: process.cwd(),
+      },
+    },
+    rules: {
+      // Basic TypeScript rules that work without type information
+      "@typescript-eslint/no-unused-vars": [
+        "error",
+        {
+          argsIgnorePattern: "^_",
+          varsIgnorePattern: "^_",
+          ignoreRestSiblings: true,
+        },
+      ],
+      "@typescript-eslint/explicit-function-return-type": "off",
+      "@typescript-eslint/explicit-module-boundary-types": "off",
+      "@typescript-eslint/no-explicit-any": "warn",
+      "@typescript-eslint/no-non-null-assertion": "warn",
+      "@typescript-eslint/consistent-type-imports": [
+        "error",
+        { prefer: "type-imports", fixStyle: "inline-type-imports" },
+      ],
+      "@typescript-eslint/consistent-type-definitions": ["error", "type"],
+
+      // Override base rules for TypeScript
+      "no-unused-vars": "off", // Handled by TypeScript
+      "no-undef": "off", // TypeScript handles this
+    },
+  };
+}