For all 40 locales, move docs/i18n/<lang>/docs/<DOC>.md into the matching
subfolder (architecture/, guides/, reference/, ...). Mirror references in
docs/i18n/<lang>/{llm.txt,CHANGELOG.md,CONTRIBUTING.md,README.md} are also
rewritten to the new paths so the i18n llm.txt mirror check stays byte-equal
to the root llm.txt body.
These are mechanical moves only — actual translations remain unchanged and
will be regenerated incrementally in FASE 5 (hash-based pipeline).
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
