Vouch request: tech4242

[tech4242]

What do you want to work on?

I am the lead maintainer of https://github.com/tech4242/aquaman (open source credential isolation proxy for agents) and while trying OpenShell (looking at adding aquaman as a potential external credential driver, so OpenShell can use desktop vaults) I hit a snag: stock Docker Desktop on macOS can't start sandboxes, because its VM kernel has Landlock compiled out (CONFIG_SECURITY_LANDLOCKunset in 29.1.3 / 6.12.54-linuxkit), and the error doesn't say why. Fixing openshell doctor check, which returns all green would be a start :) I'd like to add the kernel-requirement checks to doctor and make the startup error name its RC.

Why this change?

Mac users following the quickstart hit a cryptic failure; a clear message saves them the debugging. More generally: I want OpenShell to work with the vaults people already use, without copying secrets into another store - aquaman is one angle but happy to make other contributions in this domain.

Checklist

• I wrote this request myself (not AI-generated)
• I have read CONTRIBUTING.md

[tech4242]

Filed as #4133. Also added a macOS data point to #3880.