v5.9.1

This release includes bugfixes and internal changes.

## Changes

- Enhancement: Disable the denoising strength slider for FLUX Fill, which ignores the strength parameter.
- Fix: Error when mask blur is set to 0.
- Fix: Issue with inpaint/outpainting where the output images were not masked correctly, causing what should be transparent areas (i.e. alpha 0/255) to be very slightly not-transparent (i.e. alpha 1/255). This threw off layer bounds calculations and caused gradual degradation across repeated inpainting/outpainting operations in unmasked areas.
- Fix: Error when installing certain FLUX finetunes.
- Internal: Continued iteration on model manager's internal API.
- Internal: CI workflows now use `uv`, dropped nonfunctional CUDA/ROCm workflows (we only have CPU runners anyways).

## Installing and Updating
**The new Invoke Launcher is the recommended way to install, update and run Invoke**. It takes care of a lot of details for you - like installing the right version of python - and runs Invoke as a desktop application.

Follow the [Quick Start guide](https://invoke-ai.github.io/InvokeAI/installation/quick_start/) to get started with the launcher.

If you don't want to use the launcher, or need a headless install, you can follow the [manual install guide](https://invoke-ai.github.io/InvokeAI/installation/manual/).

## What's Changed
* fix(nodes): handle zero fade size (i.e. mask blur 0) by @psychedelicious in https://github.com/invoke-ai/InvokeAI/pull/7852
* Small improvements by @jazzhaiku in https://github.com/invoke-ai/InvokeAI/pull/7842
* feat(ui, api): support for bulk client-side uploads by @maryhipp in https://github.com/invoke-ai/InvokeAI/pull/7851
* ci: streamline workflows by @psychedelicious in https://github.com/invoke-ai/InvokeAI/pull/7739
* fix(nodes): expanded masks not 100% transparent outside the fade out region by @psychedelicious in https://github.com/invoke-ai/InvokeAI/pull/7854
* feat(ui): disable denoising strength when selected models flux fill by @psychedelicious in https://github.com/invoke-ai/InvokeAI/pull/7858
* fix(mm): flux variant probing by @psychedelicious in https://github.com/invoke-ai/InvokeAI/pull/7862
* chore: prep for v5.9.1 by @psychedelicious in https://github.com/invoke-ai/InvokeAI/pull/7863


**Full Changelog**: https://github.com/invoke-ai/InvokeAI/compare/v5.9.0...v5.9.1