This commit refactors the handling of the `--upscale` parameter.
Previously, it accepted a float representing the upscaling factor,
which could be confusing for users. Now, `--upscale` functions as
a simple boolean toggle, enabling or disabling the upscaler.
This change allows users to control the upscaling factor directly
within the upscaler node itself.
This commit introduces the `--upscale <value>` parameter to the unified
prompt. When specified, the workflow automatically triggers an upscaling
operation using the provided value as the scaling factor.
For example, `--upscale 3x` will upscale the generated image by a factor of 3.