Hidden directories cause over-watching (node_modules watched) in dev

### Describe the bug

Expected behavior: Histoire excludes `node_modules` regardless of whether the project path contains a hidden directory.

Actual behavior: Histoire watches thousands of directories below `node_modules` and exits with `EMFILE` if path contains a hidden segment.

Most AI tools store their worktrees in a hidden directory by default, causing this issue transitively (only when in a worktree, fine on main checkout)

----

The workaround is to just specify stories ignored instead of relying on the default.
```
// Histoire beta.1 otherwise traverses dependencies when the project root is hidden.
storyIgnored: [
'**/node_modules/**',
'**/dist/**',
`${rootPath}/node_modules/**`,
`${rootPath}/.nuxt/**`,
],
```

### Reproduction

https://github.com/costleya/histoire-emfile-repro-hidden

Repro has a description in the README. Basically just clone and run dev.

### System Info

```shell
System:
OS: macOS 26.5.2
CPU: (10) arm64 Apple M4
Memory: 98.02 MB / 24.00 GB
Shell: 5.9 - /bin/zsh
Binaries:
Node: 24.18.0 - /Users/costleya/.nvm/versions/node/v24.18.0/bin/node
npm: 11.16.0 - /Users/costleya/.nvm/versions/node/v24.18.0/bin/npm
pnpm: 11.15.1 - /opt/homebrew/bin/pnpm
bun: 1.3.14 - /opt/homebrew/bin/bun
Browsers:
Chrome: 150.0.7871.186
Safari: 26.5.2
```

### Used Package Manager

npm

### Validations

- [x] Follow our [Code of Conduct](https://github.com/histoire-dev/histoire/blob/main/CODE_OF_CONDUCT.md)
- [x] Read the [Contributing Guidelines](https://github.com/histoire-dev/histoire/blob/main/CONTRIBUTING.md).
- [x] Read the [docs](https://histoire.dev/guide/).
- [x] Check that there isn't [already an issue](https://github.com/histoire-dev/histoire/issues) that reports the same bug to avoid creating a duplicate.
- [x] Check that this is a concrete bug. For Q&A open a [GitHub Discussion](https://github.com/histoire-dev/histoire/discussions).
- [x] The provided reproduction is a [minimal reproducible example](https://stackoverflow.com/help/minimal-reproducible-example) of the bug.

Start with the linked histoire-emfile-repro-hidden README and run its dev command to reproduce the EMFILE failure. Compare behavior when the project path contains a hidden directory with the listed storyIgnored workaround; done means node_modules is excluded in both cases without traversing thousands of dependency directories.

Written by the indexing model from the issue text.