feat: fix webpack 5 compatibility issue in webpack.base.js

[Copilot]

Issue

The CI build was failing with the following error:

[webpack-cli] Invalid configuration object. Webpack has been initialized using a configuration object that does not match the API schema.
 - configuration.node has an unknown property 'fs'. These properties are valid:
   object { __dirname?, __filename?, global? }

See: https://github.com/casbin/casbin.js/actions/runs/18438978328/job/52536865021

Root Cause

The webpack configuration in webpack.base.js was using the deprecated webpack 4 option node.fs: "empty". This option was removed in webpack 5 and is no longer supported.

Solution

Updated the webpack configuration to use the webpack 5 compatible approach by replacing:

node: {
  fs: "empty"
}

with:

resolve: {
  extensions: [ '.tsx', '.ts', '.js' ],
  fallback: {
    fs: false
  }
}

According to the webpack 5 migration guide, polyfills for Node.js core modules are no longer automatically included and must be explicitly configured via resolve.fallback.

Verification

• ✅ All unit tests pass (13/13)
• ✅ Lint passes successfully
• ✅ TypeScript compilation succeeds
• ✅ Webpack production build succeeds
• ✅ Webpack development build succeeds
• ✅ Prepack command (used in CI) succeeds

This minimal change ensures compatibility with webpack 5 while maintaining all existing functionality.

Original prompt

---

This section details on the original issue you should resolve

<issue_title>[bug] CI error needs to be fixed</issue_title>
<issue_description>See: https://github.com/casbin/casbin.js/actions/runs/18438978328/job/52536865021</issue_description>

Comments on the Issue (you are @copilot in this section)

Fixes #292

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