reqmgmt: Add Kernel Version requirements (Issue #119 initial slice)

[harunobukurokawa]

Add an initial narrow slice of Kernel Version requirements in support of #119.

Changes:

• docs/system_requirements/index.sdoc: Add ZEP-SYRS-26 — system-level parent for kernel version information
• docs/software_requirements/version.sdoc: Add ZEP-SRS-26-1 (retrieval) and ZEP-SRS-26-2 (element access)
• docs/software_requirements/index.sdoc: Register version.sdoc

Scope note:
This PR intentionally covers retrieval and major/minor/patch element access only.
Broader version or release policy requirements are out of scope.
The component name Kernel Version is used to distinguish this topic from release policy concerns;
open to renaming if the maintainers prefer Version or Build Version.

Methodology note (first trial):
This contribution is a trial of an AI-assisted requirements engineering workflow:

• Prior merged PRs were analyzed using AI to study contribution patterns and review tendencies in this repository.
• Requirement drafts were independently produced by two AI agents (Claude Code and Codex) and cross-reviewed between them before being submitted here.
• The workflow itself — using AI not only to write requirements but to analyze past PRs and perform multi-agent review — is offered as a sample approach for the community to evaluate.

Feedback on both the requirements and the AI-assisted process is welcome.

[anobli]

I would suggest replacing information by code which is less ambiguous about the return type (an encoded value of major, minor and patch level)

[anobli]

Suggested change

	The Zephyr RTOS shall provide a mechanism to retrieve the kernel version information for the present build.
	The Zephyr RTOS shall provide a mechanism to retrieve the kernel version code.

[parphane]

Could also consider simplifying to "The Zephyr RTOS shall provide a mechanism to retrieve the kernel version."

[anobli]

Same here, I would use code instead of information.

[anobli]

Also, I don't think we need to repeat "present build" as this already stated in system requirement.

Suggested change

	The Zephyr RTOS shall provide a mechanism to obtain the major, minor, and patch level elements of the kernel version information for the present build.
	The Zephyr RTOS shall provide a mechanism to obtain the major, minor, and patch level elements from the kernel version code.

[parphane]

Rework and add the concept of a "compile-time mechanism" to set these (now only the obtain/get portion is covered)

Consider "The Zephyr RTOS shall provide compile-time mechanism to define the major, minor, and patch components of the kernel version."
Could also consider 1. splitting in 3 for atomicity or 2. removing the concept of major.minor.patch from the requirement to decouple from code
2. would give "The Zephyr RTOS shall provide a compile-time mechanism to define the kernel version.""

[parphane]

Could also consider simplifying to "The Zephyr RTOS shall provide a mechanism to retrieve the kernel version."

[parphane]

Rework and add the concept of a "compile-time mechanism" to set these (now only the obtain/get portion is covered)

Consider "The Zephyr RTOS shall provide compile-time mechanism to define the major, minor, and patch components of the kernel version."
Could also consider 1. splitting in 3 for atomicity or 2. removing the concept of major.minor.patch from the requirement to decouple from code
2. would give "The Zephyr RTOS shall provide a compile-time mechanism to define the kernel version.""