Sign in with the OTA admin secret (the value of OTA_ADMIN_SECRET on the firmware API — stored as firmware-ota-admin-secret in Secret Manager).
Session is stored in an httpOnly cookie for this hostname only.
Existing deploy
firmware-ota-admin-secret (same value mounted as OTA_ADMIN_SECRET on both Run services).gcloud secrets versions access latest --secret=firmware-ota-admin-secret --project=furrensic-dev
This only generates text in your browser. Add it as a new Secret Manager version, then redeploy furrensic-firmware-cloud and furrensic-firmware-admin so both read the same value.
Signing in with Google from this page cannot read your GCP secrets — that would require a separate authenticated backend. Project owners use Secret Manager or the command above.