Add docs/ARCHITECTURE.md: system overview, source map, threading model#3791

Draft

mcfnord wants to merge 3 commits into

jamulussoftware:mainfrom

mcfnord:add-architecture-doc

Commits on Jul 17, 2026

Add docs/ARCHITECTURE.md: system overview, source map, threading model

jrd
and
claude
committed
Add key-classes section: ownership tree and per-class responsibilities

jrd
and
claude
committed
Use full AGPL license header

jrd
and
claude
committed