Refactor Mux provider to use new operations generator

[plcdnl]

Description

Completed the Mux provider implementation that was left unfinished. The provider now works correctly with Mux's image API.

Changes Made

Fixed the provider to work with Mux playback IDs as src
Implemented proper URL generation for both static thumbnails and animated content
Added automatic detection for animated content based on start/end times
Added size validation (640px limit as per Mux requirements)

Usage

<template>
  <!-- Static thumbnail -->
  <NuxtImg
    provider="mux"
    src="your-playback-id-here"
    :modifiers="{ width: 400, height: 300 }"
  />
  
  <!-- Animated content -->
  <NuxtImg
    provider="mux"
    src="your-playback-id-here"
    :modifiers="{ start: 5, end: 10, fps: 15 }"
  />
</template>

The provider now generates correct URLs like:

https://image.mux.com/{playback-id}/thumbnail.webp?width=400&height=300
https://image.mux.com/{playback-id}/animated.gif?start=5&end=10&fps=15

[robinscholz]

@plcdnl I am getting a lot of type errors, most likely due to an upstream bug: nuxt/image#1942

Once this is fixed, I'll gladly take another look!

[plcdnl]

Hi @robinscholz, this will be fixed in nuxt/image v2, which also includes Shopify Image CDN integration. I had updated the package locally but forgot to push the update to the repo — I’m already using the alpha release of nuxt/image v2.

I’m happy to have contributed, thanks for all the work you’re doing!

[robinscholz]

In that case I’d like to wait until v2 is stable and update this package then, so to not introduce an alpha-versioned peer dependency. I'll leave this PR up until then. We’ll most likely also need to update the maas provider once v2 is stable.