Kernel module runtime options: dynamic updates and per-process options

PR #8096 adds an options module parameter that is parsed once during module init, following the original drk design. This means options are global and can only be changed by unloading and reloading the module. We want to be able to 1) update options after the module has been loaded, and 2) support per-process options.

Open design points:

- Mechanism for post-init updates (sysfs, configfs, ioctl, or writable module params) and how to apply them safely while CPUs are running under DR control.
- How to identify the process the kernel is acting on behalf of. How to store and apply per-process options.
- Whether to reuse the existing user-space config infrastructure or define a kernel specific path.

Start by reviewing PR #8096 and the existing user-space config infrastructure mentioned in the issue. Compare the proposed update mechanisms and determine how options can be applied safely while CPUs run under DR control, then document process identification and per-process option storage. Done means the kernel-specific design and its relationship to the existing configuration path are defined.

Written by the indexing model from the issue text.