extract monitoring, nvidia, mailserver, cloudflared, kyverno from platform [ci skip]

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.

stacks/cloudflared/tiers.tf

@@ -0,0 +1,10 @@
+# Generated by Terragrunt. Sig: nIlQXj57tbuaRZEa
+locals {
+  tiers = {
+    core    = "0-core"
+    cluster = "1-cluster"
+    gpu     = "2-gpu"
+    edge    = "3-edge"
+    aux     = "4-aux"
+  }
+}