Phase 2 of platform stack split. 5 more modules extracted into
independent stacks. All applied successfully with zero destroys.
Cloudflared now reads k8s_users from Vault directly to compute
user_domains. Woodpecker pipeline runs all 8 extracted stacks
in parallel. Memory bumped to 6Gi for 9 concurrent TF processes.
Platform reduced from 27 to 19 modules.
