fix(CI): IdP template verification times out on free runners

[prodnull]

Problem

verify-idp-templates.yml fails when Keycloak doesn't start within 180s on free-tier GitHub Actions runners.

Root Cause

Keycloak + realm import is resource-intensive. 2 vCPU / 7GB RAM runners can't reliably finish within the timeout, especially with multiple matrix versions.

Fix

Increase MAX_WAIT to 300s and start_period to 120s. Consider sequential matrix execution.

Pre-existing — not caused by OSS/enterprise refactor.