Replace error handling for EOF in CLI input processing with errors

[catatsuy]

This pull request includes changes to the error handling in the replaceProcess and filterProcess methods of the CLI class in the internal/cli/cli.go file. The changes improve the readability and robustness of the error handling.

Error handling improvements:

• internal/cli/cli.go: Added the errors package to handle errors more effectively.
• internal/cli/cli.go: Modified the replaceProcess method to simplify the error handling logic by checking for io.EOF and other errors separately.
• internal/cli/cli.go: Modified the filterProcess method to follow the same error handling pattern as replaceProcess, improving consistency and readability.