Refactor AI Config and Fix Login failure: Migrated services to a structured api directory, updated backend schemas for multiple TTS/STT providers, and improved settings/chat UI coverage.

refactor(auth): decouple sandbox node from core deployment and add dedicated provisioning script

feat(auth): bootstrap Day 1 local auth fallback, migrations, and sandbox node

chore: Day 0 interactive setup script, documentation, and clean docker-compose OIDC defaults