## Motivation
Add support for FLUX.1-Kontext-dev, an image editing variant of
FLUX.1-dev
## Changes
- New FluxKontextModelAdapter: Handles Kontext's image-to-image workflow
- encodes input image as conditioning latents with special position IDs,
generates from pure noise
- Model config: 57 transformer blocks (19 joint + 38 single), guidance
scale 4.0, ImageToImage task
- Pipeline updates: Added kontext_image_ids property to PromptData
interface, passed through diffusion runner
- Model cards: Added TOML configs for base, 4-bit, and 8-bit variants
- Dependency: mflux 0.15.4 → 0.15.5
- Utility: tmp/quantize_and_upload.py for quantizing and uploading
models to HuggingFace
## Test Plan
### Manual Testing
Works better than Qwen-Image-Edit
