refactor: migrate ESLint configuration to flat config and remove redundant rule files

- replace legacy .eslintrc files with flat eslint.config.js
- consolidate eslint globals for improved code clarity
- enable prefer-const and no-unused-vars off in *.js for flexibility
- remove unused import statements and redundant eslint directives from epic-games.js and aliexpress.js
- standardize function parameter syntax to arrow with parentheses omitted where safe
- add comments marking unused but retained functions for reference

.forgejo/workflows/.eslintrc.cjs

@@ -1,36 +0,0 @@
-module.exports = {
-  env: {
-    node: true,
-    es2021: true,
-    es6: true,
-  },
-  extends: [
-    'eslint:recommended',
-  ],
-  parserOptions: {
-    ecmaVersion: 'latest',
-    sourceType: 'module',
-  },
-  rules: {
-    'no-unused-vars': ['warn', {
-      varsIgnorePattern: '^_',
-      argsIgnorePattern: '^_',
-    }],
-    'no-undef': 'error',
-    '@stylistic/js/comma-dangle': ['error', 'always-multiline'],
-    '@stylistic/js/arrow-parens': ['error', 'as-needed'],
-  },
-  plugins: [
-    '@stylistic/js',
-  ],
-  globals: {
-    screenshot: 'readonly',
-    cfg: 'readonly',
-    URL_CLAIM: 'readonly',
-    COOKIES_PATH: 'readonly',
-    BEARER_TOKEN_NAME: 'readonly',
-    notify: 'readonly',
-    authenticator: 'readonly',
-    prompt: 'readonly',
-  },
-};

.forgejo/workflows/.eslintrc.json

@@ -1,25 +0,0 @@
-{
-  "env": {
-    "node": true,
-    "es2021": true
-  },
-  "extends": [
-    "eslint:recommended"
-  ],
-  "parserOptions": {
-    "ecmaVersion": "latest",
-    "sourceType": "module"
-  },
-  "rules": {
-    "no-unused-vars": "warn",
-    "no-undef": "error"
-  },
-  "globals": {
-    "cfg": "readonly",
-    "URL_CLAIM": "readonly",
-    "authenticator": "readonly",
-    "prompt": "readonly",
-    "notify": "readonly"
-  }
-}
-