build: Update ESLint to v9 (#16639)

packages/@n8n/imap/eslint.config.mjs

@@ -0,0 +1,16 @@
+import { defineConfig } from 'eslint/config';
+import { baseConfig } from '@n8n/eslint-config/base';
+
+export default defineConfig(baseConfig, {
+	rules: {
+		'unicorn/filename-case': ['error', { case: 'kebabCase' }],
+		'@typescript-eslint/consistent-type-imports': 'error',
+		'n8n-local-rules/no-plain-errors': 'off',
+
+		// TODO: Remove this
+		'@typescript-eslint/no-unnecessary-boolean-literal-compare': 'warn',
+		'@typescript-eslint/prefer-nullish-coalescing': 'warn',
+		'@typescript-eslint/no-floating-promises': 'warn',
+		'import-x/order': 'warn',
+	},
+});