[Bug]: `container image load -i <missing-file>` writes the error to stdout

[realrajaryan]

I have done the following

• I have searched the existing issues
• If possible, I've reproduced the issue using the 'main' branch of this project

Steps to reproduce

Run image load with a missing input file and redirect stdout/stderr:

$ container image load -i /path/that/does/not/exist >stdout.txt 2>stderr.txt
$ echo $?
1

$ cat stdout.txt
File does not exist /path/that/does/not/exist

$ cat stderr.txt

Problem description

Related to #642. The command fails but writes the error to stdout and leaves stderr empty. User-facing errors should go to stderr so scripts can separate command output from failures.

Environment

- OS: macOS 26.4.1 (25E253)
- Xcode: Xcode 26.4.1 (17E202)
- Container: container CLI 0.12.3 (build: release, commit: f989901)

Code of Conduct

• I agree to follow this project's Code of Conduct