Build 30

Claude code generated docs for Suvriddhi

Adds a full documentation set covering the whole repo for new
contributors: architecture overview, getting started, Buildroot usage,
Linux/rcS boot fundamentals, the OTA update & rollback system, backend
and frontend development guides, contribution guidelines (including the
mandatory human review of AI-generated code), and tips for navigating
the ~2.3M-line repo. Root README.md now indexes into suvriddhi_docs/.

Co-Authored-By: Claude

Reviewed by the human.