- nginx: use alias for BASE_PATH fallback so static assets resolve
correctly when deployed under a sub-path (fixes white page on K8s)
- base.html: remove dead template refs (chat, notes, projects) that
caused html/template to fail silently with Content-Length: 0
- login hero: rebrand from "Chat Switchboard" to "Switchboard Core",
update tagline and feature pills to reflect platform pivot
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>