fix(nuxt): handle relative baseURL in nitro runtime config

[danielroe]

🔗 Linked issue

resolves #23831

❓ Type of change

• 📖 Documentation (updates to the documentation, readme or JSdoc annotations)
• 🐞 Bug fix (a non-breaking change that fixes an issue)
• 👌 Enhancement (improving an existing functionality like performance)
• ✨ New feature (a non-breaking change that adds functionality)
• 🧹 Chore (updates to the build process or auxiliary tools and libraries)
• ⚠️ Breaking change (fix or feature that would cause existing functionality to change)

📚 Description

Nitro currently doesn't handle or support being passed a relative baseURL. I think it also doesn't particularly make sense for Nitro. So this change simply makes the url absolute instead.

I also ship an improvement in the manifest handling, to use the path utils we already have for giving us the build asset dir rather than reimplementing. However, this change wasn't needed to fix the bug; it's merely an optimisation I discovered in the process of resolving the bug..

📝 Checklist

• I have linked an issue or discussion.
• I have updated the documentation accordingly.

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[abhay-agarwal]

This change breaks our electron app configuration (e.g. nuxt-electron) which requires relative URLs. When downgrading from Nuxt 3.8.1 -> 3.7.0, setting baseURL: "./" turns paths in index.html to relative URLs, while in 3.8.1 this setting does nothing. Is there a way to regain this functionality in 3.8.1? Alternatively, is there a way to package a nuxt electron app so that it works with absolute URLs?

[danielroe]

You should be able to override this change by setting nitro.runtimeConfig.app.baseURL to the previous value. (This PR only changed the default.)

[abhay-agarwal]

Ah I see, I was setting a different baseURL runtimeConfig variable, not the nitro one.