Move backspace handling from GeneralKeyboardIME to dedicated BackspaceHandler

[Nishthajain7]

Terms

• [x] I have searched open and closed feature requests
• [x] I agree to follow Scribe-Android's Code of Conduct

Description

The GeneralKeyboardIME class has grown too large, and while #426 already addresses this issue, a significant amount of backspace-related logic remains in this file.

To improve code organization and maintainability, this logic should be extracted into a dedicated BackspaceHandler class. This would:

• Make the GeneralKeyboardIME class more focused and readable.
• Makes it easier for future contributors to understand the backspace handling.
• Improve testability of backspace-related behavior.

Contribution

No response

[andrewtavis]

Thanks for the issue, @Nishthajain7! Maybe we can continue on the current PR for #426 now, and I can assign you here for a future contribution?