fix(cli): add test and fix for argv readonly handling

[Zenvila]

Summary

This PR introduces a failing test for the argv bug related to readonly handling in the CLI,
and provides a fix to ensure proper argument parsing.

Changes

• Added new test case in tests/cli/test_cli_readonly.cpp to reproduce the bug.
• Implemented fix in CLI initialization to correctly handle readonly argv.
• Updated CMake configuration to include the new test.

Motivation

Previously, the CLI would incorrectly handle readonly cases with argv,
leading to unexpected behavior. This PR ensures that the issue is reproducible
via a test and then properly resolved in the code.

Testing

• Verified the new test fails before the fix.
• Confirmed the test passes after the fix.
• All existing tests still pass.

Related

Fixes #

[Zenvila]

Kindly review the request

[Zman350x]

Is there a reason this CLI flag was given its own parser instead of just being registered as a subcommand the same way every other CLI flag is handled? And unless I'm reading your PR wrong, you're implementing a whole new feature here (read-only mode), not just adding a test for an existing feature, so why is this marked as a test/fix instead of a feature?