6de78fe270
826-line doc covering: tech stack, tenancy hierarchy, full message pipeline (G1+G2), all 55 DB models with field descriptions, 4 auth realms, all API endpoints, member portal routes, AI dev handoff spec (queue payloads + how to write ContentDraft output back), environment variables, repo structure, migration workflow, and known gaps. Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>