[skip ci] Get rid of eslint

Dependency needs to be kept because "eslint-plugin-unused-imports" imports from "eslint/use-at-your-own-risk" at load time

tools/eslint-plugin-header.cjs

@@ -0,0 +1,29 @@
+/*
+ * Copyright (C) Contributors to the Suwayomi project
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/.
+ */
+
+// Thin wrapper around @tony.ganchev/eslint-plugin-header that removes
+// `meta.defaultOptions`. The defaults are already applied in the rule's
+// `normalizeOptions()`, but oxlint validates `defaultOptions` against the
+// schema independently (unlike ESLint which merges first), causing a load
+// failure.
+
+"use strict";
+
+const plugin = require("@tony.ganchev/eslint-plugin-header");
+
+const { defaultOptions, ...meta } = plugin.rules.header.meta;
+
+module.exports = {
+    meta: { name: "eslint-plugin-header" },
+    rules: {
+        header: {
+            ...plugin.rules.header,
+            meta,
+        },
+    },
+};