- Update canvas slice's to track the current base model architecture instead of just the optimal dimension. This lets us derive both optimal dimension _and_ grid size for the currently selected model.
- Update all bbox size utilities to use derived grid size instead of hardcoded values of 8 or 64
- Review every damned instance of the number 8 in the whole frontend and update the ones that need to use the grid size
- Update the invoke button blocking logic to check against scaled bbox size, unless scaling is disabled.
- Update the invoke button blocking to say if it's width or height that is invalid and if its bbox or scaled, for both FLUX and the T2I adapter constraints
