Add Secure Boot signing guide

[Cuda-Chen]

Add Secure Boot signing guide.

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Summary by cubic

Add a Secure Boot signing guide and link it from the README so users can load simplefs.ko on UEFI Secure Boot systems. The guide shows Ubuntu commands to install linux-headers-$(uname -r), mokutil, kmod, and openssl; generate and enroll a MOK key via mokutil/MOK Manager; sign the module and verify with modinfo—with the README noting disabling Secure Boot as an alternative.

^{Written for commit 06da008. Summary will update on new commits.}

[cubic-dev-ai]

1 issue found across 2 files

Prompt for AI agents (unresolved issues)

Check if these issues are valid — if so, understand the root cause of each and fix them. If appropriate, use sub-agents to investigate and fix each issue separately.


<file name="README.md">

<violation number="1" location="README.md:36">
P3: New Secure Boot sentence contains grammar errors that hurt readability</violation>
</file>

<sub>Reply with feedback, questions, or to request a fix.

Re-trigger cubic</sub>

[jserv]

This change is not specific to simplefs. Instead, it is a general Linux kernel module notice. Consider to contribute to LKMPG: https://github.com/sysprog21/lkmpg