feat: allow sharp format options

[Ceres6]

Changes

Allow sharp format options (e.g. https://sharp.pixelplumbing.com/api-output#avif)

Testing

I haven't added any tests yet, just opening to see if the feature is desired and this a good approach. However I'm not sure how to test this, trying all combinations would be impossible, maybe mocking to check options are actually passed is an option

Docs

I will add the change to the config reference once the api is decided.

cc @Princesseuh as discussed on Discord

[github-actions]

This PR is blocked because it contains a minor changeset. A reviewer will merge this at the next release if approved.

[codspeed-hq]

CodSpeed Performance Report

Merging #13073 will not alter performance

_{Comparing Ceres6:feat/sharp-format-options (5cd2ca5) with main (e36837f)}

Summary

✅ 6 untouched benchmarks

[ematipico]

@Ceres6 if there has been a discussion on Discord, it would be useful to link here the thread/topic/message, so it will provides us more context.

[ematipico]

I don't see anything wrong in adding more options, however since the PR lacks context, and it doesn't describe how these options will be used by our end users (lack of tests, changeset or even description), I find it very difficult to give a proper review.

[Ceres6]

Here is the thread although it wasn't a long discussion.

The context is that for some webs where image quality is critical having those extra options would be great. My use case is a photographers portfolio where compression to avif in images with smooth white backgrounds appear riddles, so options as effort or lossless provide better customisation.

The change is to be able to pass that in config like:

import { defineConfig } from 'astro/config'

export default defineConfig({
  image: {
    // Example: Enable the Sharp-based image service with a custom config
    service: {
       entrypoint: 'astro/assets/services/sharp',
       config: {
         formatConfig: {
           avif: {
             effort: 9,
             lossless: true,
           },
         },
       },
     },
  },
})