[Bug]: Webpack fsCache does not work with @storybook/nextjs framework

[sentience]

Describe the bug

The Storybook Next.js framework uses webpack internally to build Storybooks for Next.js projects.

The Storybook webpack builder supports an fsCache option to enable disk-based caching, which greatly improves incremental build performance in webpack-based Storybook projects.

When the fsCache option is enabled in a Storybook project that uses the Next.js framework, however, the disk-based cache does not work, and the Storybook build outputs a large number of webpack.cache.packFileCacheStrategy warnings. As a result, Next.js projects cannot benefit from the significant speed boost afforded by the webpack disk cache.

Storybook config

import { StorybookConfig } from "@storybook/nextjs"

export default {
  stories: ["../example/**/*.stories.(ts|tsx)"],
  framework: {
    name: "@storybook/nextjs",
    options: {
      builder: {
        fsCache: true,
      },
    },
  },
  addons: [],
} satisfies StorybookConfig

Reproduction link

https://github.com/sentience/storybook-nextjs-webpack-cache-issue-demo

Reproduction steps

1. git clone https://github.com/sentience/storybook-nextjs-webpack-cache-issue-demo.git
2. cd storybook-nextjs-webpack-cache-issue-demo
3. pnpm i
4. pnpm storybook dev

System

Storybook Environment Info:

  System:
    OS: macOS 15.1
    CPU: (8) arm64 Apple M1
    Shell: 5.9 - /bin/zsh
  Binaries:
    Node: 18.19.1 - ~/Developer/storybook-nextjs-webpack-cache-issue-demo/.devbox/nix/profile/default/bin/node
    Yarn: 1.22.22 - ~/Developer/storybook-nextjs-webpack-cache-issue-demo/.devbox/virtenv/nodejs/corepack-bin/yarn
    npm: 10.2.4 - ~/Developer/storybook-nextjs-webpack-cache-issue-demo/.devbox/nix/profile/default/bin/npm
    pnpm: 9.12.3 - ~/Developer/storybook-nextjs-webpack-cache-issue-demo/.devbox/virtenv/nodejs/corepack-bin/pnpm <----- active
  Browsers:
    Chrome: 130.0.6723.119
    Safari: 18.1
  npmPackages:
    @storybook/global: ^5.0.0 => 5.0.0 
    @storybook/nextjs: ^8.4.3 => 8.4.3 
    @storybook/types: ^8.4.3 => 8.4.3 
    storybook: ^8.4.3 => 8.4.3

Additional context

This problem seems to have existed since the introduction of @storybook/nextjs in Storybook 8.0.