WIP: New Foundation Model

[tarun-menta]

Integration of the new foundation model. Major changes are:

• Moving the foundation model into its own reusable class. The prediction loop and cache have now changed to a static shape with our custom sliding window logic
• Refactor layout and recognition to use the foundation predictor

TODOs:

• Implement multi-token prediction
• Cache logic is slow due to batch-wise looping. This needs to be vectorized
• Surface top-k for layout