refactor(cloud/certificate): Migrate final errors to typed vars

[robaa12]

Prerequisite checklist

• Read the contribution guidelines regarding submitting new changes to the project;
• Tested your changes locally.

Description of changes

This PR is a scoped follow-up for #102 , focused on internal/cli/kraft/cloud/certificate/*.
It migrates non-wrapped final errors to typed package-level errors using errors.go per touched subpackage.

Updated subpackages:

• internal/cli/kraft/cloud/certificate/list
• internal/cli/kraft/cloud/certificate/get
• internal/cli/kraft/cloud/certificate/remove
• internal/cli/kraft/cloud/certificate/create

What changed:

• Added package-level errors.go files in each subpackage above.
• Replaced non-wrapped final fmt.Errorf("...") returns with typed errors.
• Kept wrapped operational/contextual errors (...: %w) unchanged.
• Preserved contextual details where appropriate by wrapping typed errors.

[craciunoiuc]

Hmm, I meant per command block, so in this case cloud/certificate for example

[robaa12]

Got it , Just to confirm the implementation direction for both PRs (cloud/scale and cloud/certificate):

Would it be acceptable to centralize typed errors in a dedicated subpackage:

internal/cli/kraft/cloud/scale/scaleerr/errors.go
internal/cli/kraft/cloud/certificate/certerr/errors.go

The reason for a dedicated subpackage rather than a plain errors.go directly inside scale/certificate is to avoid Go import cycles , the command-block package already imports its subcommands, so subcommands can't import it back. A sibling scaleerr/certerr package sidesteps this cleanly.

If this looks good, I'll apply the refactor consistently across both PRs.

[robaa12]

Hey , @craciunoiuc
Done! Moved typed errors into internal/cli/kraft/cloud/certificate/certerr/errors.go and updated create/get/list/remove to use certerr.Err.... Removed all per-subcommand errors.go files.

Went with a certerr subpackage rather than package certificate directly to avoid import cycles while keeping everything centralized at the command-block level. Let me know if you'd like anything adjusted!

Could you please take another look and confirm this matches what you had in mind?