When BIZGAZE_LOGIN_URL is configured, verify credentials ONLY against BizGaze
(no local-password fallback) so stale in-app accounts can't shadow a BizGaze
login. Everyone is then provisioned into the same tenant, restoring the admin's
team-scoped "see all sessions" report.

- login: BizGaze-only when the IdP is configured; local path kept for dev/tests
- provisionFromBizgaze: keep role in sync with BizGaze (isAdmin) on every login;
  optional ADMIN_EMAILS allowlist as a lockout safety net
- block POST /api/users (add local agent) when BizGaze is the IdP — this is what
  previously split tenants
- scripts/migrate-bizgaze-only.js: one-time, dry-run-by-default cleanup that
  deletes pre-BizGaze local accounts (no sso_user_created audit entry)

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

User-facing
- New post-login home (/home): chat rail + Share/Connect (embedded) + Meeting; login lives here when logged out
- Landing: "Log in with BizGaze" + no-login screen share
- Console replaced by a role-scoped Dashboard (/dashboard): admins see all team sessions, others see only their own; stats + CSV/PDF export
- Recordings saved as MP4 (H.264/AAC) with WebM fallback; old .webm still downloadable
- Fix: duplicate "Sign in" on the login card

Auth / integration
- BizGaze as identity provider: /api/login validates against BIZGAZE_LOGIN_URL (env-gated) and provisions a local user
- Phase 2 start: /api/v1 alias for all /api routes; Authorization: Bearer accepted across HTTP + WS; login returns a token (for native desktop/mobile clients)

Backend refactor (Phase 1, behavior-preserving)
- Split server.js into config/lib/session/presence/routes/static/signaling + repos (data-access) + bizgaze (service)
- All SQL behind repos.js, tenant-scoped (tenantId == team_id for now)
- e2e updated to current flow (21/21 pass before and after)

Docs: ARCHITECTURE.md (target architecture + phased plan), CLAUDE.md repo layout, .env.example BIZGAZE_LOGIN_URL

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>