Group docs into intent-based subfolders so the topic each file covers is visible
from the directory layout: architecture/, guides/, reference/, frameworks/,
routing/, security/, compression/, ops/. Adds an empty diagrams/ placeholder
(populated in FASE 4) and a navigable docs/README.md index. Files were moved
with git mv so history is preserved. Internal cross-doc links were rewritten
to point at the new subfolder paths.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
