Fix text cursor display in Textbox.

[BFNOC]

Before fix text cursor in notepad.exe:

After fix text cursor in notepad.exe:

[kirides]

if i remember correctly this was intentional as otherwise a black cursor disappears on dark-themed windows, eg. VS Code, maybe there is a better way to fix this, perhaps by checking the bounding-box of the cursor in the image, and if it's mostly white-ish use black, or else white

Or figure out if there is a way to properly do it

[BFNOC]

I tried adding a detection function to determine the cursor color.
Also I fixed the problem of the animation color being wrong when the cursor state is busy.
Before fix busy cursor:

After fix busy cursor:

I would like to point out that the code was modified with the assistance of AI, I hope you don’t mind.