Bug: Terminal background doesn't apply fully when changing theme for linux executable (text boxing)

[tecnolgd]

• When changing the application theme via changeTheme(), only the background directly behind printed text is updated. The surrounding empty terminal areas, trailing spaces, and prompt lines retain the terminal emulator's default background color, creating an ugly "boxed text" effect.
• The codebase uses standard ANSI SGR escape sequences (e.g., \033[47;30m). These sequences only apply attributes to subsequently printed characters—they do not globally change the terminal emulator's canvas background. Clearing the screen with \033[2J does not repaint the empty lines with the new color.