The hard minimum memory requirement is wrongly presented as "recommended" and non-fatal

Version & Environment

Redpanda version: (use rpk version): v26.1.4
OS: Ubuntu 24.04

What went wrong?

If you start Redpanda with not enough memory it fails with an error:

Failure during startup: std::runtime_error (Memory: '...' below recommended: '...')

This is fine, but if it’s a hard requirement then:

1. it shouldn’t describe the minimum as just "recommended"
2. the SEVERITY given by rpk redpanda check for the Free memory per CPU [MB] row should be Fatal, not Warning

What should have happened instead?

1. It should say "below minimum:"
2. The SEVERITY should be Fatal

How to reproduce the issue?

1. Start Redpanda on a server with not enough RAM.

Start by tracing the startup memory error that reports memory as "below recommended," then locate the rpk redpanda check implementation for the Free memory per CPU [MB] row. Done means the message says "below minimum" and that row reports Fatal severity; the payload names no files or tests, so search by these exact strings first.