Maps viable chat-switchboard v0.39.x concepts onto core's extension-first
architecture. Classifies every component as trash/mod/add/keep. Key decisions:
per-stage audience (team/public/system) replacing binary entry_mode, branch_rules
for conditional routing and stage skipping, public surfaces as a kernel capability.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
