Portal Book New submissions returned 401 when a customer lingered in the
multi-step wizard. SSO-bridge portal sessions (POST /api/portal/session-from-auth)
are now minted with a 30-min idle TTL and slid forward on each authenticated
/api/portal/* request, bounded by an 8h absolute cap from startedAt.
- portalSession.ts: validatePortalSession extends expiresAt to now+30m for
reason="sso-bridge" sessions only (staff-initiated impersonation untouched),
capped at startedAt+8h; write skipped below a 60s slide threshold.
- portal.ts: session-from-auth mint TTL aligned to the 30-min idle window
(matches the staff-console impersonation idle model). dev-session unchanged.
- Tests: sliding extends, stays valid past original window, bounded by max
lifetime, no-slide for staff sessions, no resurrection of expired sessions.
- UAT_PLAYBOOK.md §4.8: TC-API-8.17/8.18 (slide-on-activity, slow-wizard submit).
Co-Authored-By: Paperclip <noreply@paperclip.ing>