Complete live S-grade consumer proof once session cookies are available: KARTESESSIONCOOKIE=<cookie STARBOARDS

[sarthakagrawal927]

Work

1. Complete live S-grade consumer proof once session cookies are available:
   KARTE_SESSION_COOKIE=<cookie> STARBOARD_SESSION_COOKIE=<cookie> pnpm run smoke:consumer-auth -- --require-authenticated, then re-run proof:s.

Context

Migrated from STATUS.md on 2026-07-29 when Fleet made GitHub Issues the sole operational work queue.

This issue is the to-do. Link the implementing pull request with Closes #<issue>; the linked pull request makes the work in progress, and merge + issue closure makes it done.