build: convert eslint.config to typescript and add our plugin (#1112)

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## PR Checklist

- [x] Addresses an existing open issue: fixes #1099 
- [x] That issue was marked as [`status: accepting
prs`](https://github.com/JoshuaKGoldberg/eslint-plugin-package-json/issues?q=is%3Aopen+is%3Aissue+label%3A%22status%3A+accepting+prs%22)
- [x] Steps in
[CONTRIBUTING.md](https://github.com/JoshuaKGoldberg/eslint-plugin-package-json/blob/main/.github/CONTRIBUTING.md)
were taken

## Overview
This change migrates the eslint config to typescript, and adds our
plugin's recommended config.

Tested locally to verify our plugin is working as expected. (This'll be
great as an e2e smoke test)


![screenshot](https://github.com/user-attachments/assets/e745417f-3520-4b8e-bdf0-079dbc3e6152)

Author: michaelfaith

eslint.config.js eslint.config.tseslint.config.js renamed to eslint.config.ts

@@ -11,6 +11,8 @@ import * as regexp from "eslint-plugin-regexp";
 import yml from "eslint-plugin-yml";
 import tseslint from "typescript-eslint";
 
+import packageJson from "./src/index.js";
+
 export default tseslint.config(
 	{
 		ignores: [
@@ -26,7 +28,9 @@ export default tseslint.config(
 	},
 	{ linterOptions: { reportUnusedDisableDirectives: "error" } },
 	eslint.configs.recommended,
+	// eslint-disable-next-line @typescript-eslint/no-unsafe-argument, @typescript-eslint/no-unsafe-member-access -- https://github.com/eslint-community/eslint-plugin-eslint-comments/issues/214
 	comments.recommended,
+	// eslint-disable-next-line @typescript-eslint/no-unsafe-argument, @typescript-eslint/no-unsafe-member-access -- https://github.com/eslint-community/eslint-plugin-eslint-plugin/issues/487
 	eslintPlugin.configs["flat/recommended"],
 	jsdoc.configs["flat/contents-typescript-error"],
 	jsdoc.configs["flat/logical-typescript-error"],
@@ -111,4 +115,8 @@ export default tseslint.config(
 			"n/no-unsupported-features/node-builtins": "off",
 		},
 	},
+	{
+		extends: [packageJson.configs.recommended],
+		files: ["package.json"],
+	},
 );

package.json

@@ -81,6 +81,7 @@
 		"eslint-plugin-regexp": "2.9.0",
 		"eslint-plugin-yml": "1.18.0",
 		"husky": "9.1.7",
+		"jiti": "^2.4.2",
 		"jsonc-eslint-parser": "2.4.0",
 		"knip": "5.60.0",
 		"lint-staged": "16.1.0",

pnpm-lock.yaml

@@ -10,6 +10,7 @@ describe("configs", () => {
 		const eslint = new ESLint({
 			baseConfig: plugin.configs.recommended as Linter.Config,
 			fix: true,
+			overrideConfigFile: true,
 		});
 		const code = await readFile(
 			resolve(import.meta.filename, "../../../package.json"),