CONTRIBUTING.md links to yiisoft/docs are all 404 (files moved to src/internals/)

[jhansonpk]

All 8 documentation links in .github/CONTRIBUTING.md point at the repository
root of yiisoft/docs, but those files now live under src/internals/. Every
one of them 404s, including the five under # Prerequisites — the documents a
first-time contributor is told to read before contributing.

Because this file is the template every package is scaffolded from, the same
broken links are already present verbatim in the packages. I checked
yii-runner-http, router, di and db: all four carry 7 of these 8 links and
are byte-identical on the link set.

Reproduction

Open any link under # Prerequisites, e.g.
https://github.com/yiisoft/docs/blob/master/006-git-commit-messages.md → 404.

Verified 2026-08-16, all 8 targets:

file	docs/blob/master/	docs/blob/master/src/internals/
001-yii-values.md	404	200
003-roadmap.md	404	200
004-namespaces.md	404	200
005-development-tool.md	404	200
006-git-commit-messages.md	404	200
007-exceptions.md	404	200
008-interfaces.md	404	200
010-code-style.md	404	200

The root of yiisoft/docs no longer contains any numbered .md file.

Suggested fix

Repoint the 8 links to https://github.com/yiisoft/docs/blob/master/src/internals/<file>.

Possible prevention

yiisoft/docs already ships a .markdown-link-check.json, but the checker does
not appear to cover the CONTRIBUTING.md files carried by the downstream
packages — which is likely why this went unnoticed. Extending the check to the
template (and/or to the packages) would catch the next relocation.

I am happy to open the PR for the link fix if that is useful — please let me know
whether contributions require a CLA or DCO sign-off, as I could not find either
documented in yiisoft/.github, in the package CONTRIBUTING.md files, or in
src/internals/.

[samdark]

I'd repoint to the rendered docs at https://yiisoft.github.io/docs/internals/ instead.